Subtraction Strategies and Techniques

Mrs. Gracie introduces Go Math Grade 2 Lesson 5.2, focusing on subtraction strategies using unifix cubes. She demonstrates solving 81 - 14 and 84 - 16 by breaking down numbers into tens and ones. Alternative methods like using a number line and splitting numbers are also discussed, emphasizing quick and efficient problem-solving techniques.

What is the main reason Mrs. Gracie mentions for having mismatched blocks?

• She likes colorful blocks.

• She prefers using different types of blocks.

• She sent many blocks home for homework.

• She lost some blocks.

In the first problem, what number are we subtracting from 81?

• 12

• 16

• 18

• 14

What is the result of 81 minus 1?

• 82

• 81

• 79

• 80

How does Mrs. Gracie suggest making subtraction easier?

• By guessing the answer.

• By adding numbers first.

• By using a calculator.

• By breaking down numbers into tens and ones.

What is the result of 81 minus 10?

• 71

• 70

• 72

• 69

What is the result of 81 minus 11?

• 70

• 69

• 68

• 71

What is the final answer for 81 minus 14 using the strategy discussed?

• 66

• 67

• 69

• 70

What is the first step in solving 81 minus 14 according to the strategy?

• Add 10 first.

• Subtract a whole 10 first.

• Subtract 5 first.

• Subtract 14 directly.

How many ones are subtracted after taking away a whole ten in 81 minus 14?

• Four

• Two

• One

• Three

In the second problem, what number are we subtracting from 84?

• 14

• 20

• 16

• 18