Here are four scores from a school sports day, all jumbled up: 120, 210, 102 and 201. We will line them up from lowest to highest by comparing one column at a time.
Start with the hundreds. 102 and 120 both have 1 hundred, while 201 and 210 both have 2 hundreds. The scores with fewer hundreds come first, so the 1-hundred pair goes before the 2-hundred pair.
When hundreds tie, move to the tens. For 102 and 120: 102 has 0 tens and 120 has 2 tens, so 102 is smaller. Order so far: 102, then 120.
Now the two with 2 hundreds. Tens again: 201 has 0 tens and 210 has 1 ten, so 201 comes next, then 210.
Full order from lowest to highest: 102, 120, 201, 210. Always start at the hundreds, and only move right when a column ties.
Give five seconds of quiet think-time on which score looks lowest, then take two or three hands. Do not confirm the full order yet.
Work the set on the board, column by column:
1. Hundreds: 102 and 120 have 1; 201 and 210 have 2. The 1-hundred pair comes first.
2. Tens on that pair: 102 has 0 tens, 120 has 2, so 102 then 120.
3. Tens on the 2-hundred pair: 201 has 0 tens, 210 has 1, so 201 then 210.
Full line: 102, 120, 201, 210.
Slip to watch: pupils who pick 120 as smallest by glancing at digits, or who skip straight to units. Hammer the same move, start at hundreds, only move right on a tie.
Look at these three numbers. We order them by comparing column by column. Watch where we look first when the hundreds match, and where we go next when the tens match too.
120, 210, 102: start at the hundreds. 210 has 2 hundreds so isn't smallest; 120 and 102 tie on 1 hundred, so move to tens. 120 has 2 tens, 102 has none. Order: 102, 120, 210.
305, 350, 35: the trap is length. Ask which is the odd one out before revealing 35 is smallest (two digits). 305 and 350 both have 3 hundreds, split on tens: 305 has none, 350 has 5. Order: 35, 305, 350.
444, 404, 440: all share 4 hundreds, so hundreds can't decide. Tens: 404 has none so goes first; 440 and 444 both have 4 tens. Split on units: 440 has none, 444 has 4. Order: 404, 440, 444.
Keep hammering the same move: find the smallest, then the next, comparing column by column and only moving right when a column ties.
Today we work through these sets together, dragging each number into a line from smallest to largest. We'll start with 130, 103, 113 — three numbers that look alike, so we'll say each one aloud first. Which number are you sure goes first each time?
This round is for talking it through together — pupils take turns at the board and the class agrees or corrects out loud.
For 130, 103, 113 the hundreds all tie at 1, so the whole decision lives in the tens and units — a good chance to slow the class down and read each number carefully. Rotate three or four pupils; the class confirms each placement before the next drop.
In your maths copy, copy this set of numbers, then rewrite them in order from smallest to largest:
When you have your line, read it aloud quietly to yourself to check it climbs — each number should be a little bigger than the one before it.
Walk the room glancing at whether pupils spotted that 56 comes first because it has only two digits. No individual marking — this is whole-class copybook practice, not assessment.
Now for two full sets of four, hardest last. First we'll order 506, 560, 56, 605 — the two-digit 56 catches people out, so we'll check the digit count first. Then 711, 717, 171, 177, where every number shares the same digits and only the columns tell them apart. Which two are easiest to mix up?
These are the practice questions — pupils take turns at the board, check each answer, and the class confirms before moving on. Keep the board work brisk rather than over-explaining.
In the first set (506, 560, 56, 605), watch for pupils dropping 56 into the middle — reinforce that fewer digits means smaller. The second set (711, 717, 171, 177) is the key one: all four use the digits 7, 1 and 1, so pupils must read column by column. 171 and 177 begin with 1 hundred, so they come before the 700s; then the units split 171 from 177 and 711 from 717. Rotate four pupils across the two sets.
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