Patterns and Number Sequences — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
The pattern 4, 8, 12, 16 continues with 18.
Corrected: The pattern 4, 8, 12, 16 continues with 20.
Each number grows by 4: 4, 8, 12, 16. Adding 4 to 16 gives 20, so the next number is 20, not 18.
2. Fix the sentence:
The rule for 50, 45, 40, 35 is add 5.
Corrected: The rule for 50, 45, 40, 35 is subtract 5.
The numbers get smaller: 50, 45, 40, 35. Each step goes down by 5, which means the rule is subtract 5, not add 5.
3. Fix the sentence:
In the pattern 6, 12, 18, 24, the next number is 28.
Corrected: In the pattern 6, 12, 18, 24, the next number is 30.
Skip-counting by 6 gives 6, 12, 18, 24, 30. Adding 6 to 24 lands on 30, not 28.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. The pattern 100, 90, 80, 70 follows the rule subtract 10.
From 100 to 90 is a drop of 10, and the same drop happens between 90 and 80 and between 80 and 70. The rule is subtract 10.
2. What comes next in 15, 20, 25, 30, 35?
These numbers count by 5s, so after 30 comes 35.
3. In the pattern circle, square, triangle, circle, square, the next shape is triangle.
The shapes repeat in the group circle, square, triangle. Two shapes of the new group are showing, so the missing one is triangle.
4. An input-output table uses the rule add 3. If the input is 9, the output is 12.
Add 3 to the input of 9 to get the output: 9 + 3 = 12.
Part C: True or False?
Read each statement. Circle True or False.
1. The pattern 20, 18, 16, 14 follows the rule subtract 2.
True False
True. From 20 to 18 is a drop of 2, and the same drop happens at every step, so the rule is subtract 2.
2. A growing pattern always repeats the same group of items.
True False
False. A repeating pattern uses the same group again and again, but a growing pattern gets bigger or changes each step instead of repeating.
3. The next number after 25, 30, 35, 40 is 45.
True False
True. The pattern grows by 5 each time, so adding 5 to 40 gives 45.