Solving word problems with fractions, decimals and percentages
A word problem tells a short story. Use four steps: understand what is asked, plan what to do, solve it, then check the answer.
Key idea
Understand → Plan → Solve → Check. Look for words like of (multiply), left (subtract) and total (add).
A worked word problem
Worked example
A ribbon is 1 m long. Aina uses ¼ m. How much is left?
Understand: we want the part left.
Plan: subtract the part used from the whole.
Solve: 1 − ¼ = ¾ m.
Check: ¼ + ¾ = 1 m. ✓ So ¾ m is left.
Another type
For percentages, change the percent to a fraction or a decimal first. A shirt costs RM50 with 20% off. Since 20% = 1/5, the discount is 1/5 of RM50 = RM10. So the shirt now costs RM50 − RM10 = RM40. For fractions of a group, remember that "of" means multiply: half of 40 pupils is ½ × 40 = 20 pupils. Draw a simple picture or bar if it helps you picture the parts.
Remember
- "of" usually means multiply.
- Change % to a fraction or decimal to calculate.
- Always check your answer makes sense.