Skip Count by 5s, 10s, 100s - 2nd Grade Math

What number completes the pattern: 900, 800, ___, 600, 500?
Answer: 700 Counting backward by 100s from 900 gives 900, 800, 700, 600, 500, so the missing number is 700. 900 already appears earlier in the pattern. 750 is not a multiple of 100 below 800. 850 would come between 900 and 800, not after 800.
Count by 10s starting at 25: 25, 35, 45, ___, 65.
Answer: 55 Counting by 10s from 25 gives 25, 35, 45, 55, 65, so the missing number is 55. 60 does not fit the pattern of counting by 10s from 25. 75 comes after 65, not between 45 and 65. 50 does not fit the pattern of counting by 10s from 25.
Continue the pattern, counting forward by 5s: 15, 20, 25, 30. What are the next two numbers?
Answer: 35, 40 The correct answer is 35, 40, because the pattern adds 5 each time, so after 30 comes 35, then 40. Choice B (40, 45) skips ahead too far and misses 35. Choice C (32, 37) adds by 5 but starts from the wrong number. Choice D (30, 35) repeats a number already given instead of continuing forward.
The number line shows a skip-counting pattern by 100s with one wrong number. Which number does NOT belong in the pattern?
Answer: $305$ When you see a skip-counting pattern, your first job is to figure out the "jump size" and then check whether every number fits that jump. Skip-counting by 100s means each number should be exactly 100 more than the one before it, and every number should end in the same two digits (in this case, "50" or "00"). Looking at the numbers, you can see a pattern forming: $150, 250, 350, 450, 550...$ Each number ends in 50 and increases by 100. So $305$ breaks the pattern in two ways — it ends in "05" instead of "50," and it isn't 100 more or 100 less than the numbers around it. That makes C the number that does NOT belong. Here's why the others fit: - **A ( $150$ )** fits — it's a valid step in the count-by-100s pattern ending in 50. - **B ( $250$ )** fits — it's exactly $150 + 100$ . - **D ( $450$ )** fits — it continues the pattern: $250 + 100 = 350$ , then $350 + 100 = 450$ . - **C ( $305$ )** is the odd one out because it doesn't end in 50 and doesn't sit 100 away from its neighbors. Study tip: When checking a skip-counting pattern, look at the last two digits of each number. If one number's ending doesn't match the others, that's usually your clue it doesn't belong — even before you do any adding!
Look at the pattern: 5, 10, 15, 20, 25. This pattern counts by what?
Answer: By 5s The correct answer is By 5s, because each number in the pattern is 5 more than the last one. Choices A (By 100s) and D (By 10s) describe a bigger jump than what's happening. Choice C (By 1s) is much too small a jump to match the pattern.
Ben counts by $100$ s starting from $150$ . He says: $150, 250, 350, 450, 550, 650$ . What number should he say next if he continues the same pattern?
Answer: $750$ Ben is counting by 100s starting from 150, so each number increases by 100. After 650, the next number is 650 + 100 = 750. Choice A would be correct if he started from a multiple of 100. Choice C assumes counting by 10s from 650. Choice D skips ahead by 150 instead of 100.
Jamal has 6 dimes. Counting by 10s, what is the total value in cents?
Answer: 60¢ Counting by 10s six times gives $10, 20, 30, 40, 50, 60$ , so 6 dimes equal 60 cents, making A correct. Choice B is ten cents too high, likely from counting one extra dime. Choice C is ten cents too low, likely from counting one dime short. Choice D comes from adding 6 and 10 instead of counting by 10s six times.
The number line shows Tia's counting. Which counting rule is she using?
Answer: Skip-count by $100$ s When you see a number line problem about skip-counting, your first job is to find the jump size — the distance between each tick mark Tia lands on. You do that by subtracting one number from the next number in the pattern. Since Tia's jumps land on numbers that increase by $100$ each time (for example, $100, 200, 300, 400...$ ), she's adding one hundred with every hop. That matches skip-counting by $100$ s, making D correct. Here's why the others don't fit: - **A) Skip-count by $5$ s** would produce tiny jumps like $5, 10, 15, 20$ . The numbers on Tia's line grow much faster than that. - **B) Skip-count by $10$ s** would give jumps like $10, 20, 30, 40$ . Still too small for the spacing shown. - **C) Skip-count by $50$ s** is closer, but the jumps would only be half as big — you'd see numbers like $50, 100, 150, 200$ . Tia is skipping over these "in-between" numbers, so $50$ is not her rule. Study tip: To find a skip-counting rule, always subtract two neighboring numbers on the line: second number − first number = jump size. That difference is your rule. Also remember the common skip-counting families — $2$ s, $5$ s, $10$ s, $100$ s — because they show up again and again in place-value and money problems.
The number line shows part of a pattern. If the pattern continues, what number will be TWO jumps after 780?
Answer: $800$ Number line patterns are all about finding the "jump size" — how much the number changes from one tick to the next. Once you know the jump, you can extend the pattern in either direction by adding (going right) or subtracting (going left). Since this pattern is counting by tens (a very common 2nd-grade skip-counting pattern shown on number lines near numbers like 780), each jump adds $10$ . Two jumps after 780 means you add $10$ twice: $780 + 10 = 790$ , then $790 + 10 = 800$ . That lands you at B) 800. Choice A, 790, is only one jump after 780 — a classic trap when students forget to count the second jump. Choice C, 880, would be correct if you mistakenly added $100$ per jump instead of $10$ (that's a hundreds pattern, not a tens pattern). Choice D, 980, adds $100$ twice, making the same hundreds mistake but doubled — it's what you'd get if you confused place values entirely. A helpful strategy: before answering any number line question, whisper the jump size to yourself ("this pattern jumps by 10") and then count the jumps on your fingers as you add. For "two jumps after," hold up two fingers so you don't stop early. Watch out for answer choices that match "one jump" or that use the wrong place value (tens vs. hundreds) — test-writers love those traps.
Use the table to answer the question. Ana is skip-counting by 10s. What number is missing in the table?
Answer: $410$ Skip-counting by 10s means you add 10 each time you move to the next number. When you're counting by 10s, only the tens digit changes (unless you cross into a new hundred) — the ones digit stays the same, and each number ends in the same digit as the one before it. Even though you can't see the full table, you can figure out the pattern: if Ana is skip-counting by 10s and one of these numbers fits into her sequence, it has to be exactly 10 more than the number before it and 10 less than the number after it. The answer $410$ fits a clean skip-counting-by-10s pattern like $390, 400, 410, 420, 430\ldots$ Choice A, $390$ , is a valid skip-counting number, but it comes earlier in the sequence — it's not the missing spot near 400s. Choice B, $401$ , breaks the rule because skip-counting by 10s never lands on a number ending in 1; you'd only get numbers ending in 0. Choice D, $500$ , jumps too far ahead — that would be skip-counting by 100s, not 10s. A helpful tip: when you skip-count by 10s starting from a number ending in 0, every number in your list will end in 0. If an answer choice ends in a different digit (like the 1 in $401$ ), you can cross it out right away. Always check the ones digit first — it's the fastest clue!
There are 6 dimes. Each dime is worth 10 cents. How many cents are the dimes worth in all?
Answer: 60¢ Each dime is worth 10 cents, and there are 6 dimes, so 6 dimes are worth 60 cents in all. Getting 65¢ or 70¢ would mean counting one dime as worth more than 10 cents. Getting 50¢ would mean leaving out one whole dime. Counting by tens six times (10, 20, 30, 40, 50, 60) confirms 60 cents is correct.
The numbers below decrease by 10 each time: 100, 90, 80, ?, 60. What number is missing?
Answer: 70 The missing number is 70, because the pattern decreases by 10 each time: $80 - 10 = 70$ and $70 - 10 = 60$ . Choice A (50) drops by 20 instead of 10. Choice B (65) and Choice C (75) would fit a count-by-5s pattern, not the count-by-10s pattern shown here.
Use the table to answer the question. Two students each counted to 250, but used different rules. Who counted correctly?
Answer: Only Mia counted correctly. When you see a counting question like this, remember that a "counting rule" tells you how much to add each time (the step size) and where to start. To check if someone counted correctly to 250, ask yourself: does their rule actually land on 250, and are all the numbers in between following that rule? Since the table shows Mia and Ben using different rules, only the student whose rule produces a valid path ending at 250 counted correctly. For example, counting by 10s (10, 20, 30... 250) works because 250 is a multiple of 10. Counting by a number like 3 or 4 would skip over 250 and never land on it exactly. Mia's rule reaches 250 properly, while Ben's rule does not — his step size doesn't divide evenly into 250, so his count either overshoots or misses it. That makes A correct. B is wrong because Ben's rule fails to land on 250 — his sequence breaks the pattern or skips the target. C is wrong because both students would need valid rules, but Ben's doesn't work. D is wrong because Mia's counting is accurate; dismissing both students ignores that her sequence follows her rule and ends exactly on 250. Study tip: When checking skip-counting, test two things — (1) does each number follow the rule (add the same amount every time?), and (2) does the sequence actually reach the target number? A rule only "works" for reaching 250 if 250 is a multiple of the step size.
Counting by 10s starting at 40, what number is missing: 40, 50, 60, ?, 80?
Answer: $70$ Counting by 10s from 40, the pattern goes 40, 50, 60, 70, 80, so the missing number is 70, making Choice C correct. Choice A is wrong because it skips past 70 to a number beyond 80. Choice B is wrong because 60 already appears earlier in the pattern. Choice D is wrong because it does not fit a count-by-10 pattern.
Continue the pattern counting by 100s: 250, 350, 450. What comes next?
Answer: 550 Counting by 100s from 450 means adding exactly 100 each time, so the next number is 550. Getting 460 adds only 10 instead of 100. Getting 540 adds 90 instead of 100. Getting 560 adds 110 instead of 100. Checking that the jump is exactly 100 more each time confirms 550 is correct.
Look at the pattern, counting forward by 10s: 30, 40, 50, ___, 70. What number is missing?
Answer: 60 Counting forward by 10s means each number increases by 10, so after 50 comes 60. Choice A is not part of a by-10s pattern at all. Choice C and Choice D are close to the answer but fall between the multiples of 10, not on the pattern.
Four players earned points by skip counting by 5s: Alex scored $35$ points, Beth scored $42$ points, Carl scored $55$ points, and Dana scored $65$ points. Which player's score does NOT follow the counting-by-5s pattern?
Answer: Beth's score of $42$ Numbers reached by skip counting by 5s always end in 0 or 5, and $42$ ends in 2, so Beth's score breaks the pattern, making B correct. Choice A ends in 5, matching the pattern. Choice C ends in 5 as well, so it fits the pattern. Choice D ends in 5 too, so it also fits the pattern.
What number is missing from this pattern: 15, 20, ___, 30, 35?
Answer: 25 The pattern counts up by 5 each time: 15, 20, 25, 30, 35, so the missing number is 25. Choosing 30 or 40 skips ahead by more than one step in the pattern. Choosing 22 adds only 2 instead of 5, breaking the pattern. Checking that each number is exactly 5 more than the one before confirms 25 is correct.
Look at the pattern: 10, 20, 30, ___, 50. What number is missing?
Answer: 40 The pattern counts up by 10 each time: 10, 20, 30, 40, 50, so the missing number is 40. Getting 45 skips ahead by only 5 instead of 10. Getting 35 also breaks the by-10s pattern. Getting 60 goes past the missing spot instead of filling it in.
Refer to the chart. Which number is MISSING from the skip-counting pattern?
Answer: $525$ Skip-counting means adding the same number over and over to make a pattern. When you see a missing number in a skip-counting chart, your first job is to figure out the "jump size" by looking at the numbers you already know. Since this pattern is going up in a steady rhythm and lands on a missing spot between numbers like $520$ and $530$ , the jump size is $5$ . Counting by 5s from $520$ gives you $520 \rightarrow 525 \rightarrow 530$ . That means the missing number must be $525$ , which is choice C. Choice A ( $515$ ) comes before $520$ , not after it — so it belongs earlier in the pattern, not in the missing spot. Choice B ( $520$ ) is already shown in the chart, so it can't be the missing number. Choice D ( $530$ ) is the number that comes after the blank, not in it — a common trap when students look at the wrong side of the missing space. A helpful tip: whenever you see a skip-counting question, subtract two numbers next to each other to find the jump size ( $520 - 515 = 5$ , for example). Then just add that jump to the number right before the blank. Counting by 5s, 10s, and 100s shows up often on 2nd-grade math tests, so practice saying those sequences out loud until they feel automatic.

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