This is a teaching and assessment tool for VAAP 8M-PSPFA 2a The student will solve algebraic equations using simple addition and subtraction. Answer key included.
I explicitly teach this concept first with the part-part-whole method. Next, using manipulatives such as unifix cubes students have to build the equation. Then they write the equation with an x. Next, I show them how they take away the part they know. I show them how that looks as a subtraction equation and we practice writing the problem as a subtraction problem. Finally we solve the equation to find the unknown part, or x. Then I have students write x = ___ (their answer). I explain to students they just did algebra. This tickles them!
This is an 8th grade standard for alternative assessment in Virginia; however it can be used in lower grades to practice finding the missing addend.