Missing Addend

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Missing Addend · Grade 1 · Worksheet 3

1. ? + 8 = 15 Answer: 7 Solution: The equation is ? + 8 = 15. To find the missing number, think about what number, when added to 8, equals 15.
   Full step-by-step solution

   Step 1: The equation is ? + 8 = 15. Step 2: To find the missing number, think about what number, when added to 8, equals 15. Step 3: You can count up from 8 until you reach 15: 9, 10, 11, 12, 13, 14, 15. That is 7 more numbers. Step 4: Therefore, the missing number is 7.

2. Noah has 9 crayons in his box. He needs 16 crayons for his art project. How many more crayons does Noah need to find? Answer: 7 Solution: Noah wants 16 crayons in total. He already has 9 crayons. To find how many more he needs, subtract the crayons he has from the total he wants: 16 - 9.
   Full step-by-step solution

   Step 1: Noah wants 16 crayons in total. Step 2: He already has 9 crayons. Step 3: To find how many more he needs, subtract the crayons he has from the total he wants: 16 - 9. Step 4: 16 - 9 = 7. The answer is 7.

3. A triangle has 3 sides. One side is 5 cm long, another side is 4 cm long, and the total distance around the triangle is 12 cm. How long is the third side? Answer: 3 Solution: Add the two known side lengths: 5 cm + 4 cm = 9 cm The total perimeter is 12 cm Subtract the sum of the known sides from the total perimeter: 12 cm - 9 cm = 3 cm The third side must be 3 cm long The answer is 3.
   Full step-by-step solution

   Step 1: Add the two known side lengths: 5 cm + 4 cm = 9 cm Step 2: The total perimeter is 12 cm Step 3: Subtract the sum of the known sides from the total perimeter: 12 cm - 9 cm = 3 cm Step 4: The third side must be 3 cm long The answer is 3.

4. Jordan has 4 crayons. Jordan finds some more crayons. Now Jordan has 18 crayons. How many crayons did Jordan find? Answer: 14 Solution: Jordan started with 4 crayons. After finding more, Jordan has 18 crayons. The number found is the difference: 18 - 4 = 14.
   Full step-by-step solution

   Step 1: Jordan started with 4 crayons. Step 2: After finding more, Jordan has 18 crayons. Step 3: The number found is the difference: 18 - 4 = 14. Jordan found 14 crayons.

5. Tane has 9 toy cars in a line. Some more toy cars are added to the line. Now there are 14 toy cars in total. How many toy cars were added? Draw a picture to help you solve. Answer: 5 Solution: Tane starts with 9 toy cars. Step 2: After adding some, there are 14 toy cars. Step 3: The missing number is the amount added, so we need to find ?
   Full step-by-step solution

   Step 1: Tane starts with 9 toy cars. Step 2: After adding some, there are 14 toy cars. Step 3: The missing number is the amount added, so we need to find ? in 9 + ? = 14. Step 4: Count up from 9: 10 (1), 11 (2), 12 (3), 13 (4), 14 (5). Step 5: You counted 5 numbers to reach 14. Step 6: So 9 + 5 = 14. The answer is 5.

6. Emma baked 9 cookies. Emma baked some more cookies. Now there are 14 cookies in total. How many more cookies did Emma bake? Answer: 5 Solution: Emma baked 9 cookies first. Now there are 14 cookies in total. The extra cookies baked are the difference: 14 - 9 = 5.
   Full step-by-step solution

   Step 1: Emma baked 9 cookies first. Step 2: Now there are 14 cookies in total. Step 3: The extra cookies baked are the difference: 14 - 9 = 5. Emma baked 5 more cookies.

7. ? + 7 = 16 Answer: 9 Solution: The equation is ? + 7 = 16. To find the missing number, think about what number, when added to 7, equals 16.
   Full step-by-step solution

   Step 1: The equation is ? + 7 = 16. Step 2: To find the missing number, think about what number, when added to 7, equals 16. Step 3: You can count up from 7 until you reach 16: 8, 9, 10, 11, 12, 13, 14, 15, 16. That is 9 more numbers. Step 4: Therefore, the missing number is 9.

8. Sarah has 7 stickers. She needs 16 stickers to fill her sticker book. How many more stickers does Sarah need? Answer: 9 Solution: Sarah has 7 stickers and needs 16 total To find how many more she needs, we can write: 7 + ? = 16 Start at 7 and count up to 16: 8, 9, 10, 11, 12, 13, 14, 15, 16 That's 9 more numbers Check: 7 + 9 = 16 The answer is 9.
   Full step-by-step solution

   Step 1: Sarah has 7 stickers and needs 16 total Step 2: To find how many more she needs, we can write: 7 + ? = 16 Step 3: Start at 7 and count up to 16: 8, 9, 10, 11, 12, 13, 14, 15, 16 Step 4: That's 9 more numbers Step 5: Check: 7 + 9 = 16 The answer is 9.

9. Ethan has 3 stickers. Ethan needs 6 stickers in total. How many more stickers does Ethan need to get? Answer: 3 Solution: Ethan has 3 stickers. Ethan needs 6 stickers in total. To find how many more are needed, subtract what Ethan has from what is needed: 6 - 3 = 3.
   Full step-by-step solution

   Step 1: Ethan has 3 stickers. Step 2: Ethan needs 6 stickers in total. Step 3: To find how many more are needed, subtract what Ethan has from what is needed: 6 - 3 = 3. Ethan needs 3 more stickers.