# ISEE Lower Level Math : How to find the missing part of a list

## Example Questions

### Example Question #1 : Sets

What number comes next in this sequence?

2, 3, 5, 7, 11, 13, __

Explanation:

Looking at this sequence, the most obvious thing may be the string of odd numbers. But as you look more closely, you'll notice that the 9 is missing and that there is a 2 in the list. Whenever you see a 2 in a list of odd numbers, your "prime number sensor" (not a real thing) should be on alert. As this is a list of consecutive prime numbers, the next number in the sequence is 17.

### Example Question #1 : How To Find The Missing Part Of A List

Define two sets as follows:

How many elements are in  ?

Explanation:

is the intersection of sets  and  - the set of all elements that appear in both sets. As can be seen, those elements are  - making 3 the correct choice.

### Example Question #71 : Data Analysis

Use the number sequence to answer the question.

What is the next number in the sequence?

Explanation:

The numbers in this sequence follow a pattern; each new number is twice the one that came before it. To find the next number in the sequence, multiply by two.

.

### Example Question #72 : Data Analysis

Find the missing number in the sequence:

20

24

12

16

16

Explanation:

The pattern of the sequence is to multiply each number by  to get to the next number.

and

### Example Question #5 : How To Find The Missing Part Of A List

What is the next number in this sequence?

Explanation:

Notice that the numbers in this list are growing at an increasing rate.

By the time you get to the 18, it is time to add 6:

### Example Question #1 : Sets

What number comes next in the sequence?

Explanation:

The sequence of numbers represents prime numbers, beginning with two. The next prime number in the list would be .

Note that  is not a prime number, since it is a multiple of  and .

### Example Question #161 : Data Analysis And Probability

What is the next number in this series?

Explanation:

Since the pattern is adding 2, you must add 2 to 9 to get 11.

### Example Question #8 : How To Find The Missing Part Of A List

What is the missing number in this sequence?

Explanation:

In this sequence, each number is a multiple of , and each number increases incrementally by . The multiple of  that is between  and  is ; therefore,  is the correct answer.

### Example Question #163 : Data Analysis And Probability

What is the next number in the sequence?

Explanation:

In the sequence, each subsequent number is larger than the previous number by 6.

To calculate the next number, 6 should be added to 24, resulting in 30. Thus, 30 is the correct answer.

### Example Question #1 : Sets

What is the value of  in this sequence?