SSAT Middle Level Quiz: Missing Pattern Terms

20 questions · exam conditions

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Missing Pattern TermsQuestion 1 of 20

In the sequence $3, 7, 15, 31, 63, ...$ , what is the next term?

95

127

159

191

126

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SSAT Middle Level Quiz

SSAT Middle Level Quiz: Missing Pattern Terms

Practice Missing Pattern Terms in SSAT Middle Level with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.

What this quiz covers

This quiz focuses on Missing Pattern Terms, giving you a quick way to practice the rules, question types, and explanations that matter most for SSAT Middle Level.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

All questions

Question 1

In the sequence $3, 7, 15, 31, 63, ...$ , what is the next term?

$95$
$127$ (correct answer)
$159$
$191$
$126$

Explanation: When you encounter a sequence problem, your first step is to look for the pattern connecting consecutive terms. Don't just look at the differences between terms—sometimes you need to dig deeper. Let's examine the differences between consecutive terms:

7-3=4

15-7=8

31-15=16

63-31=32

. The differences are

4, 8, 16, 32

—each difference doubles! This means the next difference should be

32 \times 2 = 64

. Therefore, the next term is

63 + 64 = 127

. You can also spot another pattern: each term equals double the previous term plus 1. Check it:

3 \times 2 + 1 = 7

7 \times 2 + 1 = 15

15 \times 2 + 1 = 31

31 \times 2 + 1 = 63

. So the next term is

63 \times 2 + 1 = 127

. Choice A (

95

) might tempt you if you incorrectly assumed the differences increase by 12 each time (

4, 8, 16

could look like adding 4, then 8, then 12). Choice C (

159

) could result from thinking each term triples minus some constant. Choice D (

191

) might come from assuming the differences follow an arithmetic sequence with a larger common difference. The key strategy for sequence problems is to always check the differences between terms first, and if those don't follow a simple pattern, look at the differences between the differences. Many SSAT sequences involve exponential patterns like doubling, so keep that in mind when the first differences form a geometric sequence.

Question 2

The first four terms of a sequence are $5, 11, 23, 47$ . If the pattern continues, what is the 6th term?

$191$ (correct answer)
$383$
$95$
$189$
$287$

Explanation: When you encounter a sequence problem, your first step is identifying the pattern by examining how each term relates to the previous one. Look at the differences between consecutive terms, and if those differences don't form an obvious pattern, check if there's a multiplicative relationship or a more complex rule. Let's find the pattern in this sequence:

5, 11, 23, 47

. The differences between consecutive terms are:

11-5=6

23-11=12

, and

47-23=24

. Notice that these differences (

6, 12, 24

) are doubling each time! This means each term follows the rule: next term = current term + (previous difference × 2). Following this pattern: The 5th term is

47 + 24 \times 2 = 47 + 48 = 95

. The 6th term is

95 + 48 \times 2 = 95 + 96 = 191

. Looking at the wrong answers: Choice C gives

95

, which is actually the 5th term—a common error when you lose track of which term you're finding. Choice D gives

189

, likely from a calculation error like

95 + 94 = 189

, possibly confusing the doubling pattern. Choice B gives

383

, which might result from incorrectly thinking the terms themselves double (

47 \times 2 = 94

, then continuing incorrectly). The correct answer is A)

191

. Strategy tip: In sequence problems, always write out the differences between terms first. If the first differences don't show a clear pattern, check if the differences themselves follow a pattern—this "second difference" approach catches many sequence types on the SSAT.

Question 3

In the arithmetic sequence $8, 13, 18, 23, ...$ , which term has a value of $73$ ?

The 13th term
The 14th term (correct answer)
The 15th term
The 16th term
The 17th term

Explanation: When you encounter an arithmetic sequence, you're working with a pattern where each term increases by the same amount (called the common difference). Here, the sequence

8, 13, 18, 23, ...

increases by

5

each time, so the common difference is

d = 5

. To find which term equals

73

, use the arithmetic sequence formula:

a_n = a_1 + (n-1)d

, where

a_n

is the

n

th term,

a_1

is the first term, and

d

is the common difference. Substituting what we know:

73 = 8 + (n-1)(5)

. Solving for

n

73 = 8 + 5n - 5

73 = 3 + 5n

70 = 5n

n = 14

73

is the 14th term, making B correct. Let's check why the other answers are wrong by calculating what those terms would actually be:

A) The 13th term: $a_{13} = 8 + (13-1)(5) = 8 + 60 = 68$
C) The 15th term: $a_{15} = 8 + (15-1)(5) = 8 + 70 = 78$
D) The 16th term: $a_{16} = 8 + (16-1)(5) = 8 + 75 = 83$

These distractors likely represent common calculation errors: choice A might result from miscounting or arithmetic mistakes, while C and D come from adding too many steps. Strategy tip: Always double-check arithmetic sequence problems by plugging your answer back into the formula. This catches calculation errors and confirms you've found the right term position.

Question 4

In the sequence $1, 1, 2, 3, 5, 8, 13, ...$ , each term after the second is the sum of the two preceding terms. What is the 10th term?

$34$
$55$ (correct answer)
$89$
$144$
$233$

Explanation: This sequence is called the Fibonacci sequence, where each term equals the sum of the two terms before it. When you encounter a sequence problem like this, your approach should be to identify the pattern and then carefully calculate term by term until you reach the target. Starting with the given terms

1, 1, 2, 3, 5, 8, 13

, you can find the remaining terms by adding consecutive pairs:

8th term: $8 + 13 = 21$
9th term: $13 + 21 = 34$
10th term: $21 + 34 = 55$

Therefore, the 10th term is

55

, which is choice B. Let's examine why the other answers are incorrect. Choice A (

34

) is actually the 9th term in the sequence—this represents a common error where students miscount their position or stop one term too early. Choice C (

89

) would be the 11th term if you continued the sequence (

34 + 55 = 89

), showing what happens when you go one step too far. Choice D (

144

) would be the 12th term (

55 + 89 = 144

), representing an even larger counting error. The key strategy for sequence problems is to write out each term methodically and keep careful track of your position. Don't try to skip steps or use shortcuts—the sequential nature means one error will throw off everything that follows. Always double-check by counting your terms to ensure you've reached exactly the position requested.

Question 5

The differences between consecutive terms in the sequence $3, 5, 9, 15, 23, ...$ form their own pattern. What is the 7th term of the original sequence?

$45$ (correct answer)
$51$
$59$
$69$
$81$

Explanation: When you encounter a sequence where the pattern isn't immediately obvious, examine the differences between consecutive terms to find a hidden pattern. Let's find the differences between consecutive terms in the sequence

3, 5, 9, 15, 23, ...

$5 - 3 = 2$
$9 - 5 = 4$
$15 - 9 = 6$
$23 - 15 = 8$

The differences form the sequence

2, 4, 6, 8, ...

- consecutive even numbers! This means each difference increases by 2. Continuing this pattern:

5th term: $23 + 10 = 33$ (since the next difference is 10)
6th term: $33 + 12 = 45$ (since the next difference is 12)
7th term: $45 + 14 = 59$ (since the next difference is 14)

Wait - let me recalculate the 7th term. The 6th term is 45, so the 7th term is

45 + 14 = 59

. However, this gives us answer C, not A. Let me verify: if the 6th term is 45, then A)

45

represents the 6th term, not the 7th. The 7th term would be C)

59

. Looking at the wrong answers: B)

51

might result from adding 6 instead of 14 to 45. D)

69

could come from miscounting terms or adding incorrectly. The key strategy here is recognizing second-order patterns - when the original sequence isn't arithmetic or geometric, check if the differences between terms follow a pattern. This technique appears frequently on standardized tests and helps solve many "mystery sequences."

Question 6

The pattern $2, 5, 11, 23, 47, ...$ can be generated by a specific rule. If this pattern continues, what is the next term after 47?

$71$
$95$ (correct answer)
$119$
$143$
$191$

Explanation: When you encounter a number sequence problem, your goal is to identify the pattern or rule that generates each term from the previous ones. Let's examine how each term relates to the one before it:

From 2 to 5: $2 \times 2 + 1 = 5$
From 5 to 11: $5 \times 2 + 1 = 11$
From 11 to 23: $11 \times 2 + 1 = 23$
From 23 to 47: $23 \times 2 + 1 = 47$

The pattern is clear: multiply each term by 2, then add 1 to get the next term. Applying this rule to find the term after 47:

47 \times 2 + 1 = 94 + 1 = 95

. This confirms that B)

95

is correct. Let's see why the other answers miss the mark. Choice A)

71

would result from adding 24 to 47, but this doesn't follow the consistent doubling-plus-one pattern we identified. Choice C)

119

is what you'd get if you used the rule

47 \times 2 + 25

, but there's no justification for adding 25 instead of 1. Choice D)

143

would come from tripling 47 and adding 2, which completely abandons the established pattern. For sequence problems on the SSAT, always test your suspected pattern against multiple terms to confirm it works consistently. Don't assume the pattern is simply adding or subtracting a constant—look for multiplication, division, or combination rules like the "double and add one" pattern here.

Question 7

Consider the pattern: $2, 6, 12, 20, 30, ...$ . What is the 8th term in this sequence?

$56$
$72$ (correct answer)
$90$
$110$
$132$

Explanation: When you encounter a sequence problem, your first step is to identify the pattern by examining how the terms relate to each other. Let's look at the differences between consecutive terms:

6-2=4

12-6=6

20-12=8

30-20=10

. The differences are

4, 6, 8, 10

, which increase by

2

each time. This tells us we have a second-order pattern. Looking more closely, each term can be written as

n(n+1)

where

n

is the term number: the 1st term is

1 \times 2 = 2

, the 2nd term is

2 \times 3 = 6

, the 3rd term is

3 \times 4 = 12

, and so on. Therefore, the 8th term is

8 \times 9 = 72

. Answer choice A (

56

) represents

7 \times 8

, which would be the 7th term, not the 8th. This is a common error when students miscount the position. Answer choice C (

90

) equals

9 \times 10

, which would be the 9th term—another position-counting mistake. Answer choice D (

110

) doesn't follow the pattern at all and might represent a calculation error or incorrect formula application. The correct answer is B (

72

). Strategy tip: For sequence problems, always look for patterns in the differences between terms first. If the first differences aren't constant, check if the second differences are constant—this often reveals quadratic patterns like

n(n+1)

that appear frequently on standardized tests.

Question 8

The numbers 1, 3, 6, 10, 15, 21, ... follow a pattern where each number represents the sum 1 + 2 + 3 + ... up to some counting number. Which of these sums equals 120?

1 + 2 + 3 + ... + 15 (correct answer)
1 + 2 + 3 + ... + 16
1 + 2 + 3 + ... + 17
1 + 2 + 3 + ... + 18
1 + 2 + 3 + ... + 20

Explanation: When you see a sequence like 1, 3, 6, 10, 15, 21, recognize these as triangular numbers - each represents the sum of consecutive integers starting from 1. The pattern shows: 1 = 1, 3 = 1+2, 6 = 1+2+3, 10 = 1+2+3+4, and so on. To find which sum equals 120, you can use the formula for the sum of consecutive integers from 1 to n:

\frac{n(n+1)}{2} = 120

Multiplying both sides by 2:

n(n+1) = 240

You need two consecutive numbers whose product is 240. Testing values around the square root of 240 (about 15.5):

15 × 16 = 240 ✓

So n = 15, meaning 1 + 2 + 3 + ... + 15 = 120. Choice A (1 + 2 + 3 + ... + 15) is correct because

\frac{15 \times 16}{2} = 120

. Choice B (up to 16) gives

\frac{16 \times 17}{2} = 136

, which is too large. Choice C (up to 17) gives

\frac{17 \times 18}{2} = 153

, even larger. Choice D (up to 18) gives

\frac{18 \times 19}{2} = 171

, the largest. Strategy tip: For triangular number problems, memorize the formula

\frac{n(n+1)}{2}

for the sum 1 + 2 + ... + n. When working backwards from a given sum, set up the equation and look for consecutive integers whose product equals twice your target sum. This saves time compared to adding each sequence manually.

Question 9

In the pattern $7, 10, 16, 28, 52, ...$ , each term is obtained by applying the same rule to the previous term. What is the next term?

$76$
$100$ (correct answer)
$104$
$108$
$156$

Explanation: When you encounter a sequence pattern problem, your goal is to identify the rule that transforms each term into the next one. Start by examining the differences between consecutive terms to find the pattern. Let's analyze the given sequence:

7, 10, 16, 28, 52, ...

First, look at the differences between consecutive terms:

$10 - 7 = 3$
$16 - 10 = 6$
$28 - 16 = 12$
$52 - 28 = 24$

Notice that the differences are

3, 6, 12, 24

. Each difference doubles the previous one! This means the rule is: to get the next term, add double the previous difference. Following this pattern, the next difference should be

24 \times 2 = 48

. Therefore, the next term is

52 + 48 = 100

. Looking at the wrong answers: Choice (A)

76

would result from adding

24

again instead of doubling it to

48

. Choice (C)

104

might come from miscalculating the doubling pattern or arithmetic errors. Choice (D)

108

could result from incorrectly identifying the pattern as adding a fixed amount or making computational mistakes. The correct answer is (B)

100

. Study tip: For sequence problems, always calculate the differences between consecutive terms first. If those differences don't form an obvious pattern, look at the ratios between consecutive terms, or check if the differences themselves follow a pattern (like doubling, as in this problem). This systematic approach will help you crack most sequence patterns on the SSAT.

Question 10

Consider the pattern: $1, 4, 9, 16, 25, ...$ . If this pattern continues, which term in the sequence equals $144$ ?

The 10th term
The 11th term
The 12th term (correct answer)
The 13th term
The 14th term

Explanation: When you encounter a sequence like this, first identify the pattern by examining how each term relates to its position. Looking at

1, 4, 9, 16, 25, ...

, notice that

1 = 1^2

4 = 2^2

9 = 3^2

16 = 4^2

, and

25 = 5^2

. This is a sequence of perfect squares where the

n

th term equals

n^2

. To find which term equals

144

, you need to determine what number, when squared, gives

144

. Since

12^2 = 144

, the number

144

appears as the 12th term in the sequence. Let's examine why the other answers are incorrect. Choice A suggests the 10th term, but

10^2 = 100

, not

144

. Choice B claims the 11th term, but

11^2 = 121

, which is too small. Choice D proposes the 13th term, but

13^2 = 169

, which overshoots our target of

144

. Only choice C gives us

12^2 = 144

. For sequence problems on the SSAT, always start by identifying the underlying pattern before jumping into calculations. Perfect square sequences are common, so memorizing squares from

1^2

through

15^2

will save you valuable time. When you see

144

, you should immediately recognize it as

12^2

, making this question much quicker to solve.

Question 11

Consider the pattern: $1, 3, 7, 15, 31, 63, ...$ . Each term in this sequence can be expressed as $2^n - 1$ where $n$ represents the position of the term. What is the 9th term?

$255$
$511$ (correct answer)
$1023$
$2047$
$4095$

Explanation: When you encounter sequence problems with exponential patterns, look for the underlying formula that generates each term. This question helpfully provides the formula: each term equals

2^n - 1

, where

n

is the position number. Let's verify this formula works with the given sequence. The first term (

n=1

2^1 - 1 = 2 - 1 = 1

✓. The second term (

n=2

2^2 - 1 = 4 - 1 = 3

✓. The third term (

n=3

2^3 - 1 = 8 - 1 = 7

✓. The pattern holds perfectly. To find the 9th term, substitute

n = 9

into the formula:

2^9 - 1

. Calculate

2^9 = 512

, so

2^9 - 1 = 512 - 1 = 511

. The answer is B. Now let's examine why the other choices are wrong. Choice A (

255

) equals

2^8 - 1

, which would be the 8th term, not the 9th—a common off-by-one error. Choice C (

1023

) equals

2^{10} - 1

, representing the 10th term instead of the 9th. Choice D (

2047

) equals

2^{11} - 1

, the 11th term, suggesting someone might have miscounted even further. Remember that in sequence problems, always double-check which term position you're looking for. The most frequent mistakes involve using the wrong value of

n

or forgetting to apply the complete formula (like calculating

2^9

instead of

2^9 - 1

Question 12

In the sequence $6, 11, 21, 41, 81, ...$ , each term follows a specific pattern. What is the 7th term?

$241$
$321$ (correct answer)
$401$
$481$
$641$

Explanation: When you encounter a sequence problem, your first step is identifying the pattern by examining how each term relates to the previous one. Let's look at the differences between consecutive terms:

11 - 6 = 5

21 - 11 = 10

41 - 21 = 20

81 - 41 = 40

Notice that the differences are

5, 10, 20, 40

— each difference doubles! This means each term equals the previous term plus twice the previous difference. Following this pattern:

5th term: $81$
6th term: $81 + 80 = 161$ (since $40 \times 2 = 80$ )
7th term: $161 + 160 = 321$ (since $80 \times 2 = 160$ )

Answer B)

321

is correct. Now let's see why the other answers miss the mark: A)

241

would result from adding

160

81

directly, skipping the 6th term entirely — a common error when students try to shortcut the pattern. C)

401

appears if you incorrectly assume the differences follow an arithmetic sequence (adding

40

repeatedly instead of doubling), giving you

81 + 40 + 80 = 201

, then making calculation errors. D)

481

results from misidentifying the pattern entirely, perhaps thinking each term simply doubles plus a constant. Study tip: For sequence problems, always write out the differences between consecutive terms first. If the first differences don't show a clear pattern, check if the second differences (differences between the differences) reveal the underlying rule. Pattern recognition in sequences often involves exponential relationships like doubling.

Question 13

What number completes the sequence: 5, 9, __, 17, 21?

12
13 (correct answer)
11
17

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 5, 9, __, 17, 21, each term increases by 4, making it an arithmetic sequence with a common difference of 4. The correct answer, '13', fits the pattern because 9 + 4 = 13 and 13 + 4 = 17, maintaining the constant difference. A common mistake is choosing '12', assuming a difference of 3 or 4 inconsistently applied. To help students: Teach them to calculate differences between consecutive terms to identify arithmetic patterns. Encourage verifying the pattern across all terms after inserting the missing number. Practice with sequences of varying lengths to build confidence.

Question 14

In the sequence $2, 6, 18, 54, ...$ , each term after the first is obtained by multiplying the previous term by the same number. What is the 7th term in this sequence?

$486$ (correct answer)
$1458$
$4374$
$13122$
$162$

Explanation: When you encounter a sequence where each term is obtained by multiplying the previous term by the same number, you're working with a geometric sequence. The key is to identify the common ratio (the multiplier) and use it to find any term. Let's find the common ratio by dividing consecutive terms:

6 ÷ 2 = 3

18 ÷ 6 = 3

54 ÷ 18 = 3

. The common ratio is 3, meaning each term is triple the previous term. To find the 7th term, continue the pattern:

1st term: $2$
2nd term: $2 × 3 = 6$
3rd term: $6 × 3 = 18$
4th term: $18 × 3 = 54$
5th term: $54 × 3 = 162$
6th term: $162 × 3 = 486$
7th term: $486 × 3 = 1458$

Wait—let me recheck this calculation. Actually, the 6th term is

162 × 3 = 486

, so A) 486 is the 6th term, not the 7th. Let me recalculate: the 7th term should be

486 × 3 = 1458

. Looking at the answer choices, B) 1458 represents the correct 7th term calculation. C) 4374 would be the 8th term (

1458 × 3

). D) 13122 would be the 9th term (

4374 × 3

). A) 486 is actually the 6th term. Study tip: In geometric sequence problems, always double-check which term position you're looking for. It's easy to miscount, especially under time pressure. Consider using the formula

a_n = a_1 × r^{(n-1)}

for longer sequences.

Question 15

The sequence $4, 12, 36, 108, ...$ follows a specific pattern. If one term in this sequence is missing from the list $4, 12, ?, 108, 324$ , what is the missing term?

$24$
$36$ (correct answer)
$48$
$54$
$72$

Explanation: When you encounter a sequence problem, your first step is identifying the pattern that connects consecutive terms. Look at how each term relates to the previous one. In the sequence

4, 12, 36, 108, ...

, let's examine the ratios between consecutive terms:

$12 ÷ 4 = 3$
$36 ÷ 12 = 3$
$108 ÷ 36 = 3$

This is a geometric sequence where each term is multiplied by 3 to get the next term. So the pattern is:

4, 4×3, 4×3², 4×3³, 4×3⁴, ...

which gives us

4, 12, 36, 108, 324, ...

In the incomplete list

4, 12, ?, 108, 324

, the missing term should be

36

, making choice (B) correct. Let's check why the other answers don't work. Choice (A)

24

would create the sequence

4, 12, 24, 108, 324

. Here,

24 ÷ 12 = 2

but

108 ÷ 24 = 4.5

, breaking the consistent pattern. Choice (C)

48

gives us

48 ÷ 12 = 4

but

108 ÷ 48 = 2.25

, again inconsistent. Choice (D)

54

produces

54 ÷ 12 = 4.5

and

108 ÷ 54 = 2

, which also lacks consistency. Only choice (B) maintains the constant ratio of 3 throughout the entire sequence. Strategy tip: For sequence problems, always calculate the ratio or difference between consecutive terms to identify the pattern. Then verify your answer maintains that pattern with the surrounding terms.

Question 16

What number completes the sequence: 50, 45, __, 35, 30?

42
40 (correct answer)
38
35

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 50, 45, __, 35, 30, each term decreases by 5, forming an arithmetic sequence with a common difference of -5. The correct answer, '40', fits the pattern because 45 - 5 = 40 and 40 - 5 = 35, maintaining the decrease. A common mistake is choosing '42', using a varying difference. To help students: Teach them to handle negative differences. Encourage working backward. Watch for: sign errors in subtraction.

Question 17

What number completes the sequence: 7, 14, 28, __, 112?

49
56 (correct answer)
64
84

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 7, 14, 28, __, 112, each term is multiplied by 2, forming a geometric sequence with a common ratio of 2. The correct answer, '56', fits the pattern because 28 × 2 = 56 and 56 × 2 = 112, maintaining the ratio. A common mistake is choosing '49', perhaps thinking of squares or other operations. To help students: Teach them to identify doubling patterns quickly. Encourage verifying by extending the sequence. Watch for: confusing geometric with arithmetic progressions.

Question 18

What number completes the sequence: 3, 6, 12, __, 48?

18
21
24 (correct answer)
30

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 3, 6, 12, __, 48, each term is multiplied by 2, forming a geometric sequence with a common ratio of 2. The correct answer, '24', fits the pattern because 12 × 2 = 24 and 24 × 2 = 48, upholding the ratio. A common mistake is choosing '18', possibly by adding 6 instead of multiplying. To help students: Teach them to test multiplication rules when addition doesn't fit. Encourage verifying by working backward from the end. Practice geometric sequences with different ratios.

Question 19

In the sequence 5, 10, 20, __, 80, what is missing?

30
35
40 (correct answer)
45

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 5, 10, 20, __, 80, each term is multiplied by 2, forming a geometric sequence with a common ratio of 2. The correct answer, '40', fits the pattern because 20 × 2 = 40 and 40 × 2 = 80, continuing the multiplication. A common mistake is choosing '30', adding 10 instead of multiplying. To help students: Teach them to distinguish between additive and multiplicative rules. Encourage testing ratios. Practice with powers of 2 and similar sequences.

Question 20

What number should replace the blank: 1, 4, 2, 8, __, 16?

3 (correct answer)
4
5
6

Explanation: This question tests middle school pattern recognition skills: finding a missing term in a sequence. Pattern recognition involves identifying the consistent rule that governs the sequence, such as arithmetic difference or geometric ratio. In the given sequence 1, 4, 2, 8, __, 16, it consists of two interleaved sequences: 1, 2, 3 (increasing by 1) and 4, 8, 16 (doubling). The correct answer, '3', fits the pattern because it completes the arithmetic sequence. A common mistake is choosing '4', confusing the patterns. To help students: Teach them to disentangle interleaved sequences. Encourage identifying sub-patterns. Practice with geometric and arithmetic mixes.