Comparing Two-Digit Numbers

Which is bigger: 47 or 52? Once your child gets why 52 wins (it has more tens), they can compare any two-digit numbers in a glance.

What we're learning

The strategy: look at the tens place first
What to do when the tens are the same
The symbols >, <, =

The look-at-tens-first strategy

When comparing two two-digit numbers:

Look at the tens place. Bigger tens = bigger number. Done.
If the tens are the same, look at the ones place. Bigger ones = bigger number.

So 47 vs 52 → 4 tens vs 5 tens → 52 wins. We never even needed to look at the ones.

So 47 vs 49 → tens are the same (4 vs 4) → ones place: 7 vs 9 → 49 wins.

This sounds trivial to an adult. To a 6-year-old, it's a meaningful strategy that replaces "I'll count up from 1 to see which I get to first."

Try it together

You'll need a notebook.

Round 1: tens-different.

Write pairs: 34 vs 51, 27 vs 60, 83 vs 19. Ask which is bigger. Reinforce: "Look at the tens place. Three tens or five tens? Five tens, so 51 is bigger."

Do 10 of these. They should get fast.

Round 2: tens-same.

Now: 34 vs 38, 52 vs 51, 19 vs 14. The tens are the same; the ones decide. Slow down here — this is where children most often slip back to counting up.

Round 3: introduce the symbols.

Show: 5 > 3 (read: "five is greater than three"), 3 < 5 (read: "three is less than five"), 5 = 5 (read: "five equals five").

The trick that helps most kids: imagine the open mouth eating the bigger number. 5 > 3 — the mouth opens toward the 5. 3 < 5 — the mouth still opens toward the 5.

Now write number pairs with the symbol blank: 47 ___ 52. They fill in <. Do 10.

Why we teach the symbols early

> and < are the gateway to inequalities, which are the gateway to algebra. A child who learned them in K-1 with concrete numbers ("five is greater than three") absorbs x > 3 in pre-algebra without confusion. A child who first met them as abstract symbols in middle school often struggles.

Doesn't have to be heavy. Five minutes a week is plenty.

Watch for

Counting up instead of using tens. "Which is bigger, 38 or 41?" Some children will answer by counting "1, 2, 3, … 38" and then "1, 2, 3, … 41" and seeing which list is longer. Correct answer, brittle method. Steer them back to: "Which has more tens?"
Confusing > and < direction. The "open mouth eats the bigger number" mnemonic helps. Drill until it's automatic.
Equals-sign overload. Some children think = means "the answer is here." That's not what it means — it means "the same as." 5 = 3 + 2 is true; 5 = 5 is true; 4 + 1 = 2 + 3 is true. All four sides are the same number. Plant this seed early.

Where this is going

You've finished K-2 mathematics! Next stop is two-digit addition and subtraction with regrouping (a.k.a. "borrowing" / "carrying"). Everything you've built — counting, bonds, doubles, place value, comparing — comes together there.