In Year 2 mathematics, children learn how to add and subtract tens to improve their number sense. This skill helps them with mental arithmetic and prepares them for more advanced calculations in later years.
In this topic, we will explain how to add and subtract 10s, provide examples, and share fun activities to make learning easy and enjoyable.
1. Understanding Place Value
Before learning how to add and subtract tens, it is important to understand place value. Every number is made up of tens and ones.
For example:
- 43 has 4 tens (40) and 3 ones (3)
- 75 has 7 tens (70) and 5 ones (5)
When adding or subtracting multiples of 10, we only change the tens place, while the ones place stays the same.
2. How to Add Tens
Adding tens is simple because we only increase the tens place while keeping the ones the same.
Example 1: 25 + 10
- 25 = 2 tens and 5 ones
- Adding 10 means adding 1 ten
- New number: 35
So, 25 + 10 = 35.
Example 2: 46 + 20
- 46 = 4 tens and 6 ones
- Adding 20 means adding 2 tens
- New number: 66
So, 46 + 20 = 66.
3. How to Subtract Tens
When subtracting tens, we reduce the tens place while the ones stay the same.
Example 1: 64 – 10
- 64 = 6 tens and 4 ones
- Subtracting 10 means taking away 1 ten
- New number: 54
So, 64 – 10 = 54.
Example 2: 85 – 30
- 85 = 8 tens and 5 ones
- Subtracting 30 means taking away 3 tens
- New number: 55
So, 85 – 30 = 55.
4. Quick Tips for Adding and Subtracting 10s
✔ Only change the tens digit
✔ The ones digit stays the same
✔ Use a number line to visualize the jump
✔ Think of it as counting in steps of 10
5. Using a Number Line
A number line is a great tool for adding and subtracting tens.
Example: 32 + 20 on a Number Line
- Start at 32
- Jump 10 to 42
- Jump another 10 to 52
- The answer is 52
Using a number line helps children see the jumps and understand the pattern.
6. Fun Activities to Practice
A. Counting in Tens
Have your child count forward and backward in tens to build confidence:
- 10, 20, 30, 40…
- 100, 90, 80, 70…
B. Tens Bingo
Create a Bingo card with numbers and call out questions like “What is 30 + 20?”. The first to complete a row wins!
C. Number Jump Game
Write numbers on the ground and have children jump forward or backward by 10s.
7. Common Mistakes and How to Fix Them
🔴 Adding or subtracting from the ones place
✅ Solution: Remind children that only the tens change.
🔴 Forgetting to count correctly
✅ Solution: Use a number line or fingers to track jumps.
🔴 Mixing up addition and subtraction
✅ Solution: Practice with real objects (e.g., adding and removing groups of 10 pencils).
8. Why Learning to Add and Subtract Tens Is Important
✔ Helps with quick mental math
✔ Builds a strong foundation for addition and subtraction
✔ Prepares children for multiplication and division
By mastering this skill, Year 2 students will find math easier and more fun!
Adding and subtracting tens is an important skill for Year 2 students. By understanding place value, using a number line, and practicing with games, children can learn this concept quickly and easily.
Encourage daily practice, make it fun and interactive, and soon your child will be a pro at adding and subtracting tens!