Number Bonds Board

About this tool

Number Bonds Board is the whole-and-parts instrument, on the projector. A number sits in the nest at the top; underneath it two trays hold the parts. A child takes one counter from a tray and carries it across, and the two parts change while the number in the nest does not. That is the whole lesson, and it is built into the material rather than written on it: there is no way to add a counter and no way to remove one, so the parts cannot stop adding up to the whole.

There is nothing to check here, because every split of a number is correct. Six is four and two, and it is also five and one, and a child who moves counters back and forth is not guessing at an answer — they are finding out that a number is made of smaller numbers, which is the idea that makes addition and subtraction one thing instead of two. The board never marks anything, never scores, and never says a split is wrong, because none of them is.

A cloth covers the nest or either tray, which turns the same board into the three questions teachers actually ask: how many altogether, and how many are hiding. Numbers up to ten, all three covers, the spoken split and the written form are free. Numbers to twenty, the record of every way a class has found, and the printable are part of the Teacher plan. The split is spoken aloud in the language of the page.

How to use it in class

• Put the board on the projector and set today's number with the plus and minus buttons — it opens on a number already.
• Ask a child to come up and carry one counter across. Tapping a tray does the same thing as dragging, so it works on a board or a tablet.
• Say the split out loud together each time: six is four and two. Turn on Say it aloud and the board says it with you, in your language.
• Cover a tray with the cloth and ask how many are hiding. Cover the nest instead and ask how many there are altogether.
• Turn on Show it written when you want the notation beside the counters — leave it off while the idea is still forming.

Classroom ideas

• Fix the number for a whole week. Monday is six, and every morning a different child finds a different way to make six.
• Cover one tray before the child carries a counter across, so the class has to work out what changed without seeing it.
• Ask for a split, then ask for the one next to it: if six is four and two, what happens if I move just one more?
• Put two ways side by side on the record and ask what is the same about them — that is where the pattern in the pairs shows up.