Number bonds to 100 bingo

Number bonds to 100 bingo uses 21 problems (x + ? = 100 for every multiple of 5 from 0 to 100), whose 21 different answers fill 4x4 cards. The caller reads "65 + ? = 100", players mark 35. With 30 cards the first bingo comes after about 6 calls.

Number Bonds to 100 Bingo
65	70	95	30
55	90	75	10
5	50	100	45
20	15	0	80

Card 1 of 30

The caller reads a problem; players mark its answer. 21 problems, 21 answers.

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Free: up to 30 different cards per set. Pro: up to 1,000.

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Updated October 23, 2026

Number bonds to 100 at a glance

What is called	21 problems: x + ? = 100 for every multiple of 5 from 0 to 100
What is on the cards	21 answers, from 0 to 100
Recommended card	4x4: 16 answers per card
Different cards possible	about 426 quadrillion (21 answers placed in 16 squares)
Typical level	Grade 2-3
Problems per answer	one each

Answer key: every number bonds to 100 problem by answer

21 calls, 21 squares. First marked = (21 + 1) ÷ (problems + 1), the average call at which the answer is reached in a shuffled game.

Answer	Problems the caller reads	Problems	First marked (avg. call)
0	100 + ? = 100	1	11
5	95 + ? = 100	1	11
10	90 + ? = 100	1	11
15	85 + ? = 100	1	11
20	80 + ? = 100	1	11
25	75 + ? = 100	1	11
30	70 + ? = 100	1	11
35	65 + ? = 100	1	11
40	60 + ? = 100	1	11
45	55 + ? = 100	1	11
50	50 + ? = 100	1	11
55	45 + ? = 100	1	11
60	40 + ? = 100	1	11
65	35 + ? = 100	1	11
70	30 + ? = 100	1	11
75	25 + ? = 100	1	11
80	20 + ? = 100	1	11
85	15 + ? = 100	1	11
90	10 + ? = 100	1	11
95	5 + ? = 100	1	11
100	0 + ? = 100	1	11

Self-check: number bonds to 100 answers

95 + 5 = 100
90 + 10 = 100
85 + 15 = 100
75 + 25 = 100
70 + 30 = 100
65 + 35 = 100
60 + 40 = 100
45 + 55 = 100
40 + 60 = 100
30 + 70 = 100
25 + 75 = 100
15 + 85 = 100
0 + 100 = 100

Is number bonds to 100 bingo fair?

In number bonds to 100 bingo each of the 21 answers comes from exactly 1 problem, from "0 + ? = 100" (100) to "100 + ? = 100" (0), so every square on the card has the same chance: an answer is first marked at call 11 of 21 on average, and after 5 calls each one has a 24% chance of being marked.

With 21 calls in number bonds to 100 bingo and 16 squares per card, every 4x4 card is full by call 21 at the latest, so the shuffle alone decides who shouts first.

How long a number bonds to 100 game lasts

300 simulated number bonds to 100 games (4x4, any line wins): 1 card needed 12 calls (median), 10 cards 8, 30 cards 6, with 8 in 10 games between call 5 and 8.

A class of 30 playing number bonds to 100 bingo uses 29% of the 21 calls per game, so one caller sheet covers about 3 games; a full-card game with 30 cards took 19 calls.

How to play number bonds to 100 bingo in class

Use a ten frame or bead string

Show 25 + ? makes 100 with counters: the missing part is 75. Every call in this set has the same total, so only one number changes.
Hand out the cards

Print 4x4 number bonds to 100 cards: 16 of the 21 answers (0 to 100) each, 76% coverage.
Read the problem, not the answer

Call "5 + ? = 100", pause, then the next. 21 calls, one per answer, so no square has a head start.
Check every bingo

Read back the called problems; the winner names each answer (25 + ? = 100 → 75). 30 cards: first bingo near call 6.

Example calls from this set

Four problems drawn from the number bonds to 100 caller sheet and the square each one marks.

The caller reads 0 + ? = 100

Mark 100 (the only problem with this answer)
The caller reads 70 + ? = 100

Mark 30 (the only problem with this answer)
The caller reads 40 + ? = 100

Mark 60 (the only problem with this answer)
The caller reads 45 + ? = 100

Mark 55 (the only problem with this answer)

Frequently asked questions

How many problems are in number bonds to 100 bingo?

21 problems (x + ? = 100 for every multiple of 5 from 0 to 100), with 21 different answers. The caller sheet lists all 21; the cards show only the answers.

What size card works best for number bonds to 100?

4x4. A card needs 16 different answers and the number bonds to 100 set has 21 (0 to 100), so a 4x4 card is the largest that fits. That still allows about 426 quadrillion different cards.

Does any answer come up more often than others?

No. Each of the 21 answers is reached by exactly 1 problem of the 21 (0 + ? = 100 gives 100, 100 + ? = 100 gives 0), so every square has the same chance and is first marked around call 11 on average.

How many calls until someone wins?

In 300 simulated number bonds to 100 games with 30 4x4 cards, the first line was completed after a median of 6 calls; with 10 cards after 8 calls.

Make and play

More math bingo

Square numbers 1-20 20 problems · 20 answers · 4x4
Halves of even numbers to 50 25 problems · 25 answers · 5x5