One split, four facts

Before you read anything

Seven things, two piles. Find seven small things — bottle tops, stones, beans. Put them in two piles. Any two piles.

Now write down every true number sentence your two piles say. Most people write two. There are four.

What you just made

Seven stones, four and three. Count them — the picture is not asking you to take its word for anything.

Start here

The picture you are about to meet, and where it ends up. It is the same one in module 12, with a letter in the box.

Watch a seven split

One whole of seven, cut in a different place each time. The two parts change; the seven never does.

A number bond is a whole cut into two parts. Cut 7 into 4 and 3, and you have not learned one fact. You have learned four.

Sarah

put hers in 4 and 3

Okello

put his in 5 and 2

Both of them are right, and neither has more seven than the other.

Now do it yourself

The same seven, on the screen. Drag the line through them and watch the four sentences change together — you are only moving one thing.

Every position is a true split. There is nothing here to get wrong.

Read the picture four ways

Going down the picture is adding: put the parts together. Going up is subtracting: take one part off the whole and the other part is what is left.

Why "family". The four sentences are relatives. They come from one split, so knowing any one of them means you already know the other three.

Check yourself

Six to try

Draw the bar before you answer. Some of these want a number and some want you to say which statement is true — both are reading the same picture.

1

The whole is 15. One part is 9. What is the other part?

2

$6 + \square = 14$. What goes in the box?

3

Which of these is NOT one of the facts in the split $12 = 7 + 5$?

4

Amara knows $9 + 6 = 15$. Which of these can she write down straight away, with no working?

5

Which split has two equal parts?

6

Which of these is true for every part-whole split?

Show that you have it

One fact, and the three that came free

You know that $47 + 28 = 75$. That is the only thing you are given, and it is enough for all three. If you find yourself working them out, go back and drag the split again — reading them off is the whole idea.

1

You know that $47 + 28 = 75$. Without working anything out: $75 - 28 = \square$

2

Same split. Without working anything out: $75 - 47 = \square$

3

Same split. Without working anything out: $28 + 47 = \square$

Next: Bonds without thinking The whole thing on one page