Subtract Multiples of 10

Grade 1 · mathematics · 80 practice problems · read aloud

🔊 Listen to this explanation

Subtracting Multiples of 10

🧠 What is it and Why is it Useful?

Subtracting multiples of 10 means taking away groups of ten. It's like counting back by tens! This is a super useful skill because it helps you solve big subtraction problems quickly and gets you ready for working with bigger numbers.

📝 How to Solve: Step-by-Step

  1. Look at the tens. Find the digit in the tens place in both numbers.
  2. Subtract the tens. Just subtract those two numbers.
  3. Bring the ones. The ones digit stays the same.
  4. Write the answer. Put your new tens number and the ones together!

👀 Let's Look at Examples

Example 1: 50 - 20 = ?

Step 1: Look at the tens: 5 tens and 2 tens.
Step 2: Subtract the tens: 5 - 2 = 3.
Step 3: Bring the ones: 0 ones.
Answer: 30 🎉

Example 2: 67 - 40 = ?

Step 1: Look at the tens: 6 tens and 4 tens.
Step 2: Subtract the tens: 6 - 4 = 2.
Step 3: Bring the ones: 7 ones.
Answer: 27 🎉

⚠️ Common Mistakes to Avoid

Don't subtract the ones! When you see a problem like 80 - 50, you only subtract the tens (8 - 5). The zero in the ones place just comes along for the ride.

Watch for tricky numbers. In a problem like 63 - 30, remember you are only taking away the 3 tens (30). The 3 ones in 63 stay right where they are!

💡 Tips & Tricks

Think of it as "How many tens?" 50 is 5 tens. 20 is 2 tens. 5 tens - 2 tens = 3 tens, and 3 tens is 30!

Use a hundreds chart. Find the first number, then jump up two rows (because each row is 10). Where you land is your answer!

🎯 How to Practice

  • Use base-ten blocks. Show 40 as 4 tens sticks. Take away 2 sticks. How many are left?
  • Play a game! Write problems on cards and race to solve them.
  • Ask an adult to give you quick problems like "What is 90 minus 60?" and try to answer in your head!

Practice problems

6 of the 80, worked through step by step — try them before opening the answer.

1 50 - 20 = ?

Hint: Think about subtracting tens. For example, if you have 40 and take away 10, you have 30.

Show the answer

Answer: 30

  1. Write the problem clearly. 50 minus 20 means we start with 50 and remove 20.
  2. Subtract the ones place. 50 has 0 ones, 20 has 0 ones. 0 ones minus 0 ones = 0 ones.
  3. Subtract the tens place. 50 has 5 tens, 20 has 2 tens. 5 tens minus 2 tens = 3 tens.
  4. Combine the results. 3 tens and 0 ones gives the number 30.
  5. Final answer. So, 50 - 20 = 30. We can check: 30 + 20 = 50, which matches, so the subtraction is correct.

We are solving: 50 - 20 = ?

2 90 - 40 = ?

Hint: Think about subtracting tens from tens. For example, 70 - 20 means taking away 2 tens from 7 tens.

Show the answer

Answer: 50

  1. Write down the problem. 90 - 40
  2. Understand the operation. We are subtracting 40 from 90. This means we are finding the difference between these two numbers.
  3. Subtract the ones place. The number 90 has 0 in the ones place. The number 40 has 0 in the ones place. 0 - 0 = 0 So, the ones digit of our answer is 0.
  4. Subtract the tens place. The number 90 has 9 in the tens place. The number 40 has 4 in the tens place. 9 - 4 = 5 So, the tens digit of our answer is 5.
  5. Combine the results. A tens digit of 5 and a ones digit of 0 gives the number 50.
  6. Final answer. 90 - 40 = 50

Let's solve 90 - 40 step by step.

3 80 - 30 = ?

Hint: Think about subtracting tens. For example, if you have 60 and take away 20, you're left with 40.

Show the answer

Answer: 50

  1. Write the numbers vertically aligned by place value for clarity: 80 - 30
  2. Subtract the digits in the ones place: 0 (from 80) minus 0 (from 30) equals 0. So, the ones place of the result is 0.
  3. Subtract the digits in the tens place: 8 (from 80) minus 3 (from 30) equals 5. So, the tens place of the result is 5.
  4. Combine the tens digit and ones digit: 5 (tens) and 0 (ones) gives 50.
  5. Check the reasoning: 80 is 8 tens, 30 is 3 tens. 8 tens minus 3 tens = 5 tens, which is 50. Final answer: 50

We are solving: 80 - 30 = ?

4 70 - 40 = ?

Hint: Think about subtracting tens. For example, if you have 50 and take away 20, you're left with 30.

Show the answer

Answer: 30

  1. Write the problem vertically to see the place values clearly. 70 - 40
  2. Subtract the digits in the ones place first. Ones place: 0 - 0 = 0.
  3. Subtract the digits in the tens place. Tens place: 7 - 4 = 3.
  4. Combine the results from the tens place and ones place. Tens place result is 3, ones place result is 0, so together we get 30.
  5. Check the reasoning: 70 is 7 tens, 40 is 4 tens. 7 tens minus 4 tens = 3 tens, which is 30. Final answer: 30

We are solving: 70 - 40 = ?

5 60 - 20 = ?

Hint: Think about subtracting tens from tens

Show the answer

Answer: 40

  1. Start with 60, which is 6 tens
  2. Subtract 20, which is 2 tens
  3. 6 tens - 2 tens = 4 tens
  4. 4 tens = 40

The answer is 40.

6 60 - 30 = ?

Hint: Think about subtracting tens. For example, 50 - 20 means 5 tens minus 2 tens.

Show the answer

Answer: 30

  1. 60 is the same as 6 tens
  2. 30 is the same as 3 tens
  3. Subtract the tens: 6 tens - 3 tens = 3 tens
  4. 3 tens equals 30

The answer is 30.

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