Add Multiples of 10

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Answer Key & Explanations

Add Multiples of 10 · Grade 1 · Worksheet 2

1. A rectangle is drawn with 4 rows of circles. Each row has 10 circles. How many circles are there in total? Answer: 40 Solution: We have a rectangle with 4 rows of circles, and each row has 10 circles. We are told there are 4 rows, and each row contains 10 circles. Write the multiplication.
   Full step-by-step solution

   We have a rectangle with 4 rows of circles, and each row has 10 circles. Step 1: Understand the problem. We are told there are 4 rows, and each row contains 10 circles. So the total number of circles is the number of rows multiplied by the number of circles in each row. Step 2: Write the multiplication. Total circles = number of rows × circles per row Total circles = 4 × 10 Step 3: Perform the multiplication. 4 × 10 = 40 Step 4: State the final answer. There are 40 circles in total. This works because multiplication counts the total objects in an array: 4 rows of 10 means 10 + 10 + 10 + 10 = 40.

2. Oliver picked 40 flowers from the garden in the morning and 10 flowers in the afternoon. How many flowers did Oliver pick altogether? Answer: 50 Solution: Oliver picks 40 flowers in the morning. Oliver picks 10 flowers in the afternoon. Add the two amounts: 40 + 10 = 50.
   Full step-by-step solution

   Step 1: Oliver picks 40 flowers in the morning. Step 2: Oliver picks 10 flowers in the afternoon. Step 3: Add the two amounts: 40 + 10 = 50. Oliver picked 50 flowers altogether.

3. Harper picked 10 flowers from the garden in the morning and 30 flowers in the afternoon. How many flowers did Harper pick altogether? Answer: 40 Solution: Harper picks 10 flowers in the morning. Harper picks 30 flowers in the afternoon. Add the two amounts: 10 + 30 = 40.
   Full step-by-step solution

   Step 1: Harper picks 10 flowers in the morning. Step 2: Harper picks 30 flowers in the afternoon. Step 3: Add the two amounts: 10 + 30 = 40. Harper picked 40 flowers altogether.

4. Liam has 60 building blocks in his toy box. His friend Sophia gives him 30 more building blocks to play with. How many building blocks does Liam have now? Answer: 90 Solution: Liam starts with 60 building blocks. Sophia gives him 30 more building blocks. Add 60 + 30.
   Full step-by-step solution

   Step 1: Liam starts with 60 building blocks. Step 2: Sophia gives him 30 more building blocks. Step 3: Add 60 + 30. Step 4: 60 + 30 = 90 Liam has 90 building blocks now.

5. Noah has 40 toy cars in his collection. For his birthday, his grandma gives him 50 more toy cars. How many toy cars does Noah have now? Answer: 90 Solution: Noah starts with 40 toy cars He gets 50 more toy cars Add the two amounts: 40 + 50 40 + 50 = 90 The answer is 90.
   Full step-by-step solution

   Step 1: Noah starts with 40 toy cars Step 2: He gets 50 more toy cars Step 3: Add the two amounts: 40 + 50 Step 4: 40 + 50 = 90 The answer is 90.

6. A baker made 20 cookies in the morning and 50 cookies in the afternoon. How many cookies did the baker make in total? Answer: 70 Solution: The baker made 20 cookies in the morning. The baker made 50 cookies in the afternoon. Add the morning and afternoon cookies: 20 + 50 20 + 50 = 70 The answer is 70.
   Full step-by-step solution

   Step 1: The baker made 20 cookies in the morning. Step 2: The baker made 50 cookies in the afternoon. Step 3: Add the morning and afternoon cookies: 20 + 50 Step 4: 20 + 50 = 70 The answer is 70.

7. Isabella drew 8 towers of blocks. Each tower has 10 blocks. How many blocks did Isabella draw in total? Answer: 80 Solution: Isabella drew 8 towers, and each tower has 10 blocks. To find the total number of blocks, add 10 eight times: 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10.
   Full step-by-step solution

   Step 1: Isabella drew 8 towers, and each tower has 10 blocks. Step 2: To find the total number of blocks, add 10 eight times: 10 + 10 + 10 + 10 + 10 + 10 + 10 + 10. Step 3: Add in order: 10 + 10 = 20, 20 + 10 = 30, 30 + 10 = 40, 40 + 10 = 50, 50 + 10 = 60, 60 + 10 = 70, 70 + 10 = 80. Step 4: The total number of blocks is 80. The answer is 80.

8. A triangle has 3 sides. One side is 10 cm long, another side is 20 cm long, and the third side is 30 cm long. What is the total length of all 3 sides? Answer: 60 Solution: The first side is 10 cm The second side is 20 cm The third side is 30 cm Add all three sides: 10 + 20 + 30 10 + 20 = 30 30 + 30 = 60 The answer is 60 cm.
   Full step-by-step solution

   Step 1: The first side is 10 cm Step 2: The second side is 20 cm Step 3: The third side is 30 cm Step 4: Add all three sides: 10 + 20 + 30 Step 5: 10 + 20 = 30 Step 6: 30 + 30 = 60 The answer is 60 cm.