Box Buddies Answer Key
About This Worksheet
Box Buddies is a kindergarten number-part activity that helps children fill in a missing number so two parts make a whole of 10. Each problem shows three connected boxes: one part is given, one part is blank, and the whole is 10. Children figure out which number belongs in the empty box. For example, if one part is 3, the missing part is 7 because 3 + 7 = 10. This helps young learners see 10 as a whole that can be built from two smaller numbers.
Curriculum and Grade Alignment
This worksheet is made for kindergarten learners who are practicing number combinations that make 10. The main goal is to help children identify the missing partner in a part-part-whole model. Before using this page, your child should be able to count to 10 and understand that two smaller groups can join to make one larger group. The next step is writing addition equations from these box models and solving missing-addend problems without a visual organizer. This activity supports early addition by strengthening number bonds and part-part-whole thinking.
Student Tasks
On this worksheet, students will complete twelve box problems. They will look at the part that is already given and decide what number must go in the blank so the total is 10. Some problems place the known part on the left, while others place it in the middle. The changing position helps children focus on the number relationship instead of memorizing the layout. This builds missing-number reasoning, fact fluency, and number sense.
Common Challenges and Misconceptions
Some children may write 10 in the blank because they focus on the whole instead of the missing part. Others may add the known number to 10 rather than think about what is needed to reach 10. A child may also be confused when the known part appears in a different box position. Encourage your child to say, “This part plus what makes 10?” before writing. Fingers, counters, or a ten-frame can help when a partner is not yet remembered.
Implementation Guidance
Teachers can use this worksheet after children have worked with number bonds and make-10 pairs using counters. It works well as independent practice because the model stays simple while the known part changes. Parents can use 10 small objects and separate them into two groups to match one problem before the child fills in the box. Ask the child to count both parts and say the full equation aloud. This keeps the worksheet connected to a real quantity.
Details and Features
This worksheet includes twelve part-part-whole box models with 10 shown as the whole. One part is provided and one is left blank in each problem. Large boxes make the number relationships easy for kindergarten children to see. The repeated total of 10 keeps the practice focused on complementary pairs. The printable supports number bonds, missing addends, addition readiness, and make-10 fluency.