Subtract a one-digit number from a two-digit number up to 18

key notes :

What is subtraction?

Understand subtraction ➖

Subtraction means taking away.

Example: 15 − 7 means taking 7 away from 15.

Focus on numbers up to 18 🔢

The biggest number we use here is 18.

So problems can be: 10 − 3, 12 − 8, 18 − 5, etc.

Start with counting back 👣

From the bigger number, count backwards the smaller number.

Example: 14 − 6 → start at 14 and count back 6: 13, 12, 11, 10, 9, 8 → Answer = 8

Use number line for help 📏

Draw a line from 0 to 18.

Start at the bigger number and jump back the smaller number.

Break the number if needed 🔄

Sometimes it’s easier to split the bigger number.

Example: 17 − 8 → split 17 into 10 + 7.

7 − 8 → can’t do → borrow from 10 → 17 − 8 = 9

Check your answer ✅

After subtracting, add the answer to the smaller number.

If it equals the bigger number, the answer is correct.

Example: 15 − 7 = 8 → 8 + 7 = 15 ✅

Practice with real objects 🍎

Use pencils, fruits, or toys to visualize subtraction.

Example: 12 apples − 5 apples → count what is left → 7 apples

Remember subtraction facts up to 18 💡

Some important ones:

10 − 1 = 9, 12 − 3 = 9, 15 − 5 = 10, 18 − 7 = 11

Learn with an example

Let’s practice!🖊️