Inverse Operations Addition and Subtraction Worksheet

Write two addition sums and two subtraction sums from a given set of three related numbers.

Recognize that a fact family's addition and subtraction equations use the same three numbers in different arrangements.

Generate an original three-number fact family and write its four corresponding equations.

Walk through the worked example (5, 15, 10) as a class before students begin the five remaining given triads on page 1.

Use page 2 as a partner activity: one student creates a number set and writes the four sums, then a partner checks the work.

Point out that a valid triad must let all four sums work; if a set doesn't produce four true equations, the numbers need to change.

Fact-family construction — students derive four related equations (2 addition, 2 subtraction) from a single three-number set.

Inverse-operation reasoning — students see that subtraction facts (15 - 10 = 5) and addition facts (10 + 5 = 15) from the same triad undo each other.

Two-digit addition and subtraction fluency — later triads use numbers up to 90, extending the fact-family skill beyond basic facts.

Original problem generation — students invent their own valid three-number sets on page 2 rather than only solving given ones.