Spotting structure: numbers and shapes

Mathematics · Mathematical Thinking · ages 7-8

Name ______________________ Date ____________

You know 6 x 4 = 24. What is 4 x 6?
- 20
- 24
- 28
200 + 45 = 245. If you do 300 + 45 instead, what changes?
- Only the hundreds digit
- The tens digit too
- The ones digit too
Which shape has exactly 3 sides?
- Triangle
- Rectangle
- Pentagon
You know 7 x 8 = 56. What is 56 / 8?
- 6
- 7
- 8
536 + 200 = ? Type the answer.
Answer: ______________
A shape has 4 sides, but no right angles and no parallel sides. Could it be a rectangle?
- No, a rectangle needs 4 right angles and parallel sides
- Yes, any 4-sided shape is a rectangle
- Yes, as long as it has 4 corners
You know 9 x 6 = 54 but forgot 54 / 9. What's the fastest way to find it without dividing from scratch?
- Use the same fact family: 54 / 9 = 6
- Multiply 54 x 9
- Guess and check every number from 1 to 54
Ravi says 250 + 600 = 850, then finds 250 + 700 by changing only the tens digit. Is his method right?
- No, 600 to 700 is a change in the hundreds digit, not the tens digit
- Yes, that's correct
- No, you must recalculate everything from scratch

Answer key

For grown-ups. Fold this page away before handing over the rest.

24 · Order doesn't matter in multiplication, so 4 x 6 = 24 too.
Only the hundreds digit · Adding to the hundreds place only changes the hundreds digit. 45 stays 45.
Triangle · A triangle is defined by having 3 sides and 3 corners.
7 · Multiplication and division facts are linked: since 7 x 8 = 56, 56 / 8 = 7.
736 · 200 only changes the hundreds digit: 5 becomes 7. The 36 stays the same, so 536 + 200 = 736.
No, a rectangle needs 4 right angles and parallel sides · A rectangle must have 4 right angles and 2 pairs of parallel sides, not just 4 sides.
Use the same fact family: 54 / 9 = 6 · Multiplication and division facts come in families, so 9 x 6 = 54 tells you 54 / 9 = 6 right away.
No, 600 to 700 is a change in the hundreds digit, not the tens digit · 600 to 700 changes the hundreds place, so the hundreds digit of the answer changes too: 250 + 700 = 950.