Why does my child multiply only the fractions in an equation?
Your child multiplies the fractions by the common denominator but not the other side, such as (x + 1)/2 = 4 becoming x + 1 = 4 instead of x + 1 = 8.
Why children do it
The fractions are what need clearing, so children multiply those and forget the rest. But an equation stays true only if both sides are multiplied by the same number: in (x + 1)/2 = 4, multiplying by 2 gives x + 1 = 8, not x + 1 = 4. Every term, on both sides, gets multiplied.
How to help at home
Ask them to draw an arrow to every term, on both sides, as they multiply: none can be missed.
The right way
Solve: (x + 1)/2 + (x + 7)/3 = 7
- 3(x + 1) + 2(x + 7) = 42Multiply every term by 6. Each top goes in a bracket.
- 3x + 3 + 2x + 14 = 42Expand the brackets.
- 5x + 17 = 42Collect like terms.
- 5x = 25Subtract 17 from both sides.
- x = 5Divide both sides by 5.
Find out where your child is
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Start the free checkRelated mistakes
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