Discover number bonds of 10 and 20 in this Year 2 Maths article from BBC Bitesize.

Bond investors' rising concerns around U.S. government spending and its ballooning budget deficit are contributing to a steep sell-off that has pushed Treasury prices to 17-year lows.

You can write a number bond as an addition number sentence, for example: 7 + 3 = 10. It doesn't matter which order you add numbers together, the total amount is the same.