Solving data problems
Use the 4 steps: understand the question, plan what to do, solve it, and check the answer. Read the data first, then decide whether to add, subtract or compare. Words like "in all" and "altogether" tell us to add.
Worked example
A shop sold 4 red pens and 6 blue pens. How many pens in all?
Understand: red = 4, blue = 6. Plan: add. Solve: 4 + 6 = 10. Check: 6 + 4 = 10. Answer: 10 pens.
Comparing data
How many more blue pens than red pens? We take away: 6 − 4 = 2. So there are 2 more blue pens. If a question asks how many are left, we also subtract. Always read the numbers from the data before you choose to add or take away.
Key idea
"In all" means add. "How many more" means subtract.
Remember
- Read the data carefully.
- Add to find a total.
- Subtract to compare.