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Mental Math 10 More/Less

Grade 1 · Mathematics · Worksheet 3

  1. 9 + 10 = ? Answer: ______________
  2. Emma has 18 stickers in her collection. Her friend Mia gives her 10 more stickers. How many stickers does Emma have now? Answer: ______________
  3. Sophia has 21 stickers in her sticker book. Her grandmother gives her 10 more stickers. How many stickers does Sophia have now? Answer: ______________
  4. Liam has 15 toy cars in his collection. His grandmother gives him 10 more toy cars for his birthday. How many toy cars does Liam have now? Answer: ______________
  5. Mason has 27 crayons in his art box. His teacher gives him 10 more crayons to use for a project. How many crayons does Mason have now? Answer: ______________
  6. 29 + 10 = ? Answer: ______________
  7. 19 + 10 = ? Answer: ______________
  8. Mere has 38 crayons in her art box. She buys a new pack of 10 crayons at the store. How many crayons does Mere have now? Answer: ______________
  9. Emma has 25 stickers in her collection. She finds 10 more stickers in her backpack. How many stickers does Emma have now? Answer: ______________
  10. Hana has 42 stickers in her sticker book. Her cousin gives her 10 more stickers. How many stickers does Hana have now? Answer: ______________
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Answer Key & Explanations

Mental Math 10 More/Less · Grade 1 · Worksheet 3

  1. 9 + 10 = ? Answer: 19 Solution: 9 + 10 = 19. The tens digit increases from 0 to 1.
  2. Emma has 18 stickers in her collection. Her friend Mia gives her 10 more stickers. How many stickers does Emma have now? Answer: 28 Solution: Emma starts with 18 stickers Mia gives her 10 more stickers Add the stickers together: 18 + 10 18 + 10 = 28 The answer is 28.
    Full step-by-step solution

    Step 1: Emma starts with 18 stickers Step 2: Mia gives her 10 more stickers Step 3: Add the stickers together: 18 + 10 Step 4: 18 + 10 = 28 The answer is 28.

  3. Sophia has 21 stickers in her sticker book. Her grandmother gives her 10 more stickers. How many stickers does Sophia have now? Answer: 31 Solution: Sophia starts with 21 stickers. Her grandmother gives her 10 more stickers. Add the stickers together: 21 + 10.
    Full step-by-step solution

    Step 1: Sophia starts with 21 stickers. Step 2: Her grandmother gives her 10 more stickers. Step 3: Add the stickers together: 21 + 10. Step 4: 21 has 2 tens and 1 one. Adding 10 means adding 1 more ten, so 2 tens + 1 ten = 3 tens. The ones stay as 1. Step 5: 21 + 10 = 31. Sophia now has 31 stickers.

  4. Liam has 15 toy cars in his collection. His grandmother gives him 10 more toy cars for his birthday. How many toy cars does Liam have now? Answer: 25 Solution: Identify the starting number of toy cars. Liam starts with 15 toy cars. Identify how many toy cars are added.
    Full step-by-step solution

    Step 1: Identify the starting number of toy cars. Liam starts with 15 toy cars. Step 2: Identify how many toy cars are added. His grandmother gives him 10 more toy cars. Step 3: Add the new toy cars to the original number. 15 + 10 = 25 Step 4: State the final answer. Liam now has 25 toy cars.

  5. Mason has 27 crayons in his art box. His teacher gives him 10 more crayons to use for a project. How many crayons does Mason have now? Answer: 37 Solution: Mason starts with 27 crayons. His teacher gives him 10 more crayons. Add the crayons together: 27 + 10.
    Full step-by-step solution

    Step 1: Mason starts with 27 crayons. Step 2: His teacher gives him 10 more crayons. Step 3: Add the crayons together: 27 + 10. Step 4: 27 has 2 tens and 7 ones. Adding 10 means adding 1 more ten, so 2 tens + 1 ten = 3 tens. The ones stay as 7. Step 5: 27 + 10 = 37. Mason has 37 crayons now.

  6. 29 + 10 = ? Answer: 39 Solution: 29 + 10 = 39. The tens digit increases from 2 to 3.
  7. 19 + 10 = ? Answer: 29 Solution: 19 + 10 = 29. The tens digit increases from 1 to 2.
  8. Mere has 38 crayons in her art box. She buys a new pack of 10 crayons at the store. How many crayons does Mere have now? Answer: 48 Solution: Mere starts with 38 crayons. Step 2: 38 has 3 tens and 8 ones. Step 3: She adds 10 more crayons, which is 1 more ten.
    Full step-by-step solution

    Step 1: Mere starts with 38 crayons. Step 2: 38 has 3 tens and 8 ones. Step 3: She adds 10 more crayons, which is 1 more ten. Step 4: 3 tens + 1 ten = 4 tens. The ones stay as 8. Step 5: 38 + 10 = 48. Mere has 48 crayons now.

  9. Emma has 25 stickers in her collection. She finds 10 more stickers in her backpack. How many stickers does Emma have now? Answer: 35 Solution: Emma starts with 25 stickers She finds 10 more stickers Add 25 + 10 25 + 10 = 35 Emma has 35 stickers now.
    Full step-by-step solution

    Step 1: Emma starts with 25 stickers Step 2: She finds 10 more stickers Step 3: Add 25 + 10 Step 4: 25 + 10 = 35 Emma has 35 stickers now.

  10. Hana has 42 stickers in her sticker book. Her cousin gives her 10 more stickers. How many stickers does Hana have now? Answer: 52 Solution: Hana starts with 42 stickers. Her cousin gives her 10 more stickers. Add the new stickers to the ones she already has: 42 + 10.
    Full step-by-step solution

    Step 1: Hana starts with 42 stickers. Step 2: Her cousin gives her 10 more stickers. Step 3: Add the new stickers to the ones she already has: 42 + 10. Step 4: 42 has 4 tens and 2 ones. Adding 10 means adding 1 more ten, so 4 tens + 1 ten = 5 tens. The ones stay as 2. Step 5: 42 + 10 = 52. Hana has 52 stickers now.