Skip Counting — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. What is the missing number? 30, 27, 24, ___, 18.
A) 22
B) 20
C) 21
D) 23
The sequence counts backward by 3s (30 - 3 = 27, 27 - 3 = 24), so 24 - 3 = 21, which is also exactly 3 more than 18.
2. Which sequence shows counting backward by 5s?
A) 40, 35, 30, 25, 20
B) 40, 35, 25, 20, 15
C) 40, 30, 25, 20, 15
D) 40, 35, 30, 20, 15
Counting backward by 5s means each number is 5 less than the one before, and 40 - 5 = 35, 35 - 5 = 30, 30 - 5 = 25, 25 - 5 = 20 all work perfectly.
3. If you count by 3s starting at 0, which number will you NOT say?
A) 6
B) 9
C) 14
D) 18
Counting by 3s from 0 gives 0, 3, 6, 9, 12, 15, 18, and so on. 14 is skipped because it is not a multiple of 3.
4. What number comes next? 150, 140, 130, 120, ___.
A) 100
B) 115
C) 110
D) 105
The list counts backward by 10s (each number is 10 less than the one before), so after 120 you subtract 10 to get 110.
Part B: Fill in the Blank
Write the correct answer on each line.
1. Count backward by 2s: 24, 22, 20, 18.
Counting backward by 2s subtracts 2 at each step, so 20 - 2 = 18.
2. Count by 3s: 21, 24, 27, 30, 33.
Counting by 3s, 24 + 3 = 27. You can double-check because 27 + 3 = 30, the next number in the list.
3. Count backward by 10s: 180, 170, 160, 150.
Subtracting 10 from 170 gives 160. That fits since 160 - 10 = 150, which is the next number in the list.
4. Count backward by 5s: 75, 70, 65, 60.
Going backward by 5 each step, 65 - 5 = 60, which keeps the -5 pattern steady.
5. Count by 3s: 27, 30, 33, 36, 39.
Each number is 3 bigger than the one before, so 33 + 3 = 36, which is exactly 3 less than 39.