Balance equations: justify each step

Grade 6 mathematics · 15 minutes · Equations

Solve one-step equations and check solutions by substitution.

Classroom activity

A mystery box and 7 counters balance 19 counters.

1. Draw the balance and write x + 7 = 19.
2. Explain what you can remove from both sides without changing the balance. Find x.
3. A second balance has 4 identical boxes equal to 28 counters. Write and solve its equation.
4. Check each solution by substituting it into the original equation.

With a partner, create one addition equation and one multiplication equation with whole-number solutions. Swap and check them.

Check understanding

Solve y + 9 = 23 and 5z = 45. Show a check for each solution.

Teacher guide and answers

x = 12 and the second equation is 4b = 28, giving b = 7. Checks: 12 + 7 = 19 and 4 × 7 = 28. The exit answers are y = 14 and z = 9. Ask why the operation must affect both sides. Support with drawings of equal groups; extend by writing a context for each equation.

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Grade 6 topic reference. Confirm your adopted standards; topic guidance does not certify alignment.