TEACHER EDITION
Comparing Numbers
Math Book 3 · sheet 5
Warm-up — yesterday: Place Value — Part 2
Write 2,507 in expanded form.2,000 + 500 + 7
What we are learning
Compare from the LEFT. The first place where the digits differ decides it, and nothing to the right of that matters.
How it is done — keep this beside you
These steps stay on your page while you work. If you get stuck, find the step you are on and read it again before you put your hand up.
1
Compare 3,482 and 3,479.
3,482 3,479
2
Thousands: both 3. Not decided.
3,482 3,479
3 = 3
3
Hundreds: both 4. Still not decided.
3,482 3,479
3 = 3
4 = 4
4
Tens: 8 against 7. Decided.
3,482 3,479
3 = 3
4 = 4
8 > 7
5
3,482 is greater. The ones were never needed.
3,482 3,479
3 = 3
4 = 4
8 > 7
3,482 > 3,479
Practice
I DOteacher builds it, nothing erased
Which is greater, 5,216 or 5,261?
- Thousands equal. Hundreds equal.
- Tens: 6 against 1. 6 is more.
- 5,261 > 5,216
WE DO 1together, on whiteboards
Which is greater, 4,807 or 4,870?
Go left to right and STOP at the first difference. Boards up.
- Tens: 7 against 0.
- 4,870 > 4,807
WE DO 2together, on whiteboards
Which is greater, 2,999 or 3,001?
One of these looks much bigger than it is.
- Thousands: 3 against 2.
- 3,001 > 2,999
YOU DOindependent, from the book
Book 3A p.18 — the Do section, clipped onto the slide
Ask yourself: “Have I found the first place where they differ?”
Watch for
2,999 vs 3,001 is the trap: three 9s look enormous. A child who answers 2,999 has compared how the number LOOKS rather than the leading place, which is the same error as Grade 2's 28-versus-71, one size up.
2,999 vs 3,001 is the trap: three 9s look enormous. A child who answers 2,999 has compared how the number LOOKS rather than the leading place, which is the same error as Grade 2's 28-versus-71, one size up.