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Year 3 Maths

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Working with Equations

When you write 7 - 4 = 3, or 5 + 3 = 8, you are writing an equation. An equation compares numbers using an equals sign: =. As you know, the equals sign means ‘is the same as’.

All of these are equations:

7 + 7 = 14
36 = 36
4 + 1 = 9 - 4

There's a special rule for working with equations:

Whenever you change one side of an equation, you have to make the same change to the other side so the two sides stay equal.

equation of 6 + 3 = 2 + 7

For example, you have a basket of six oranges plus a bowl of three oranges. I have two oranges in one basket and another basket that is spilling seven oranges. We each have nine oranges.
6 + 3 = 2 + 7

Now we decide to make orange juice. In an equation, when we decide to take away from one side, we have to take away from the other side as well. So, we each take five oranges to squeeze into orange juice:
6 + 3 - 5 = 2 + 7 - 5

We each have four oranges left, and a glass of fresh orange juice to drink!

equation of 6 + 3 – 5 = 2 + 7 – 5

This activity is adapted from page 239 of What Your Year 3 Child Needs to Know, which can be purchased here.