· 2 min read · Ages 5–8 · Kindergarten through Grade 2
Number bonds to 10 and 20: the sheet behind addition fluency
Three circles joined by two lines, one of them empty. It looks like a craft. It is the machine behind every addition fact your child knows.
Our kindergarten teacher sent home a sheet of circles joined by lines every week, and for a month I assumed it was an art project. It is a number bond: a whole split into two parts, one of them left blank. My son now knows every pair that makes 10 without thinking, and those sheets are why.
What the sheet looks like
The number bonds generator prints a grid of bond diagrams, each with the whole in the top circle and two parts below, joined by lines, with one circle empty. You choose the whole: 5, 6, 7, 8, 9, 10, then 12, 15, 20, 25, 50, or 100. You can keep the same whole for every problem or mix wholes across the page, and you decide what is missing: one part, the whole, or a mix. Pages hold 6 to 18 bonds, with an answer key if you want one.
Why it works
- A same-whole page of bonds to 10 is "all the ways to make 10" learned as a set, not as nine separate facts.
- A missing whole is addition and a missing part is subtraction, but the picture is identical. Kids see them as one relationship early, which saves a lot of grief in second grade.
- Wholes of 50 and 100 turn the same diagram into mental math. 37 and what make 100 is a question adults use at the checkout.
Who it suits
Five- and six-year-olds work on wholes of 5 to 10 with counters nearby. Second graders can handle mixed wholes of 20, 50 and 100 with the whole sometimes missing. If the idea of splitting a number is still new, the ten frames sheet shows the same thing with dots, and the missing addends worksheet is the same idea written as an equation.
Do bonds to 10 until they are boring. Boring is the goal.