Addition Within 100: Bridging Through Ten
Bridging through ten is the key barrier in addition within 100. Two strategies turn a hard problem into a chain of easy steps.
What bridging through ten means
The problem 27+8 requires a bridge: 27+3=30, then 30+5=35. Instead of adding 8 all at once, the child first reaches the nearest round number, then adds the remainder. This is the core strategy for addition within 100.
Strategy 1 — Bridge to the round number
Algorithm on 36+7
Step 1: how far to the next ten? 36 → 40 needs 4.
Step 2: split 7 into 4 and 3.
Step 3: 36+4=40, then 40+3=43.
The child lands on a "station" — a round number — then travels on from there.
28+5: 28+2=30, 30+3=33
47+6: 47+3=50, 50+3=53
69+8: 69+1=70, 70+7=77
85+9: 85+5=90, 90+4=94
Strategy 2 — Split by place value
Algorithm on 34+28
Step 1: tens together: 30+20=50.
Step 2: ones together: 4+8=12.
Step 3: combine: 50+12=62.
Transparent and reliable for any two two-digit numbers.
25+37: 20+30=50, 5+7=12, 50+12=62
46+38: 40+30=70, 6+8=14, 70+14=84
53+29: 50+20=70, 3+9=12, 70+12=82
Which strategy to use when
- Bridge to ten — when the second number is single-digit (27+8)
- Split by place value — when both numbers are two-digit (34+28)
- Over time the child picks the convenient one — a sign of understanding
➕ Build the base for bridging!
Our game trains addition within 20 — the foundation every bridging strategy rests on.
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