3rd Grade Solving for the Unknown Worksheet: Pick the Right Answer

The answers are 19, 15, 6, 10, 89, 14, 1 and 6, while the wrong choices show a few typical mistakes. In a, 40 = 21 + t, the choice 61 comes from adding 40 and 21 instead of subtracting. In b, n − 9 = 6, the choice 3 comes from 9 − 6. Similarly, in d, 1,000 comes from 10 × 100.

Items f and g put the letter on the right side, as in 3 = U − 11. Here, U = 14, because 14 − 11 = 3. Item d also writes 10 m with no sign between the number and the letter, which means 10 × m. This is a later grade habit, so explain it first.

A multiple choice question can be checked by trying the answers. For g, 6 = v × 6, your child tries 1 first: 1 × 6 = 6, so v = 1. If a choice does not work, they cross it out. As a result, guessing turns into checking.

The instruction says "tick the correct answer", which in the US means "check". Also, item f uses a capital U while the other letters are small. Tell your child that the size of the letter does not matter, because what counts is the missing number it stands for.

Hide some buttons in one hand and show the rest. Say: "There are 13 in all, and you see 7. How many are hidden?" Your child writes 7 + u = 13 and answers 6. Next, swap roles, and use a sum of your child's choice. Finally, check the eight boxes against the answer key on page two.