The 4 steps for data problems
Use 4 steps: 1) Understand the question, 2) Plan whether to add, subtract or use the key, 3) Solve step by step, 4) Check the answer. Read every table and chart key carefully.
Key idea
To find "how many more", subtract. To find a total, add. With a pictograph, multiply the number of pictures by the value of the key.
Two data word problems
Worked example
A pictograph shows balls, each ⚽ = 2 balls. Class A has 4 pictures and Class B has 3 pictures. How many more balls does Class A have? Solve: A = 4 × 2 = 8, B = 3 × 2 = 6, difference = 8 − 6 = 2 balls. Check: 6 + 2 = 8. Correct!
Worked example
A table shows cakes sold: Mon 5, Tue 3, Wed 4. How many altogether? "Altogether" means add: 5 + 3 + 4 = 12 cakes. Check: count again, 5 + 3 = 8, 8 + 4 = 12. Correct!
Remember
- "How many more" means subtract.
- "Altogether" means add.
- Use the key before you count.