The worksheet called "Addition Number Bonds With Answers Up to 20" features individual number bonds with single-digit addends. Students find the answers to all number bonds on first-grade pages. Students find both answers and addends on second-grade pages. That includes finding just one addend or filling in both addends.

Each page includes a total of 16 number bonds for students to answer. There's also a space at the top of the page where they write their starting and ending times to see how fast they can complete the worksheet.

Number bonds are an effective way to help students build number sense. They help students see larger numbers as two numbers added together, like seeing 12 as 2 + 10, 3 + 9, and so on. They encourage mental math, and they support both addition and subtraction, as students can use both when filling in the missing numbers.

Early learners should focus on small number bonds that contain one answer and two addends. Students should practice with numbers they're ready for, like answering number bonds to 10, and then answering number bonds to 20. As students become more proficient, you can try number bonds with multiple levels where the sum of two numbers becomes one of the numbers that must be combined with another to get the next answer.

Consider timing students as they complete number bonds. This gives you the ability to see which students are proficient and need a bigger challenge and which students need more support.