Number bonds to 10 and 20

Hello, and welcome to Myriora Maths! Quick question: seven, and what, make ten? If you knew it straight away, that's a number bond. Today, we'll learn them all.

Why do number bonds matter? Say you buy a lolly for seven pence, and pay with a ten pence coin. How much change do you get? Three pence! If you know your number bonds, you know the change straight away. They help with adding, taking away, and money, every single day.

This is a ten frame. Ten spaces, in two rows of five. Let's put in seven counters. How many spaces are empty? Three! So seven and three make ten.

Let's find every pair. Zero and ten. One and nine. Two and eight. Three and seven. Four and six. Five and five. Notice: as one number goes up, the other goes down.

Let's try one together. Six, and what, make ten? Look at the ten frame. Say your answer out loud!

Six counters leave four empty spaces. So six and four make ten. Well done if you said four!

Now, twenty. If seven and three make ten, then seventeen and three make twenty. Why? Seventeen is ten and seven. The seven and three make another ten, and two tens make twenty. It's the same bond, with an extra ten.

And here's something clever. The same bonds work with tens. Three tens and seven tens make ten tens. And ten tens make a hundred! So thirty and seventy make a hundred.

Why does this help? Try eight plus five. Take two from the five, to turn the eight into ten. Ten plus three is thirteen!

Here's a question that catches lots of people. Six, and what, make ten? Some people say three. But look at the ten frame: six and three leave one space empty. Six and four make ten.

Your turn! What goes with twelve to make twenty? Pick the right card. You've got fifteen seconds, or pause the video. Go!

Time's up! It's eight. Because two and eight make ten.

Quick review. Number bonds are pairs that make ten. Add a ten, and they make twenty. And they help you add, by making a ten first. See you next time!