Word problems with parts
These stories use fractions, decimals or percentages. Read carefully and decide what part of the whole the story is talking about.
Key idea
Use 4 steps: understand, plan, solve, check. "Left over" means subtract; "of" often means find a part.
Finding a percentage of an amount
Worked example
A class has 40 pupils. 25% wear glasses. How many wear glasses?
Plan: find 25% of 40.
Solve: 25% = ¼, so 40 ÷ 4 = 10 pupils.
Check: 10 × 4 = 40. Correct!
Working with decimals
A bottle holds 1.5 L. You drink 0.7 L. Left = 1.5 − 0.7 = 0.8 L.
Working with fractions of a group
To find 2/5 of 20 sweets, first divide by the bottom number: 20 ÷ 5 = 4. Then multiply by the top number: 4 × 2 = 8 sweets. Dividing shares the whole into equal parts, and multiplying counts how many parts we want.
Remember
- "Of" a whole → find that part.
- "Left" → subtract.
- Check the answer fits the story.