This make 100 game helps second graders find the number pairs that add up to 100 by playing: race cars, pop balloons, flip memory cards or sprint through true and false sentences. Every question gives a number such as 35 and asks what to add to make 100, so 35 + ? = 100 has the answer 65. The starting numbers are multiples of 5 from 10 to 95, so children practice number bonds to 100 using tens first. It is free, needs no sign-up, works on phones and tablets, and comes with a printable make 100 chart.
Make 100 game: see how it plays
The game below opens in Answer Race and has three more modes. The printable chart shows ten pairs that make 100 as colored bars, with a think-in-tens tip and a self-test, and the pictures show Answer Race, Balloon Pop and Memory Match on this page.
How the make 100 game works
- Answer Race: every right answer moves your car forward, and you race three computer cars to the finish flag. The first to 15 wins, and wrong taps cost time, not places.
- Balloon Pop: answers float up on balloons, and you pop the right one before it drifts off the top. The wrong balloons sit within 15 of the right answer, so children have to work out the missing number and not just guess. The game speeds up as your score climbs, and three misses ends the round.
- Memory Match: twelve face-down cards hide six questions such as 60 + ? = 100 and their six answers. Flip two at a time and match each one to its answer in as few moves as you can.
- True or False: sixty seconds on the clock. Decide whether each sentence, such as 45 + ? = 100 = 55, is right or wrong. A streak of five or more scores double.
Pairs that make 100: think in tens
The key idea is that 100 is 10 tens. If a number has 4 tens, it needs 6 more tens to make 10 tens, so 40 + 60 = 100. For numbers that end in 5, such as 35, first add 5 to reach the next ten (40), then add the tens that are still needed (60). So 35 + 65 = 100, because 5 + 60 = 65. This “make the next ten, then add tens” method is the same bridging idea children use to add within 20, now applied to bigger numbers. See also our addition within 20 game.
Number bonds to 100 game: every pair in the make 100 game
| Question | Answer | How to think |
|---|---|---|
| 10 + ? = 100 | 90 | 1 ten needs 9 more tens |
| 15 + ? = 100 | 85 | make 15 into 20 (add 5), then add 80 |
| 20 + ? = 100 | 80 | 2 tens needs 8 more tens |
| 25 + ? = 100 | 75 | make 25 into 30 (add 5), then add 70 |
| 30 + ? = 100 | 70 | 3 tens needs 7 more tens |
| 35 + ? = 100 | 65 | make 35 into 40 (add 5), then add 60 |
| 40 + ? = 100 | 60 | 4 tens needs 6 more tens |
| 45 + ? = 100 | 55 | make 45 into 50 (add 5), then add 50 |
| 50 + ? = 100 | 50 | 5 tens needs 5 more tens |
| 55 + ? = 100 | 45 | make 55 into 60 (add 5), then add 40 |
| 60 + ? = 100 | 40 | 6 tens needs 4 more tens |
| 65 + ? = 100 | 35 | make 65 into 70 (add 5), then add 30 |
| 70 + ? = 100 | 30 | 7 tens needs 3 more tens |
| 75 + ? = 100 | 25 | make 75 into 80 (add 5), then add 20 |
| 80 + ? = 100 | 20 | 8 tens needs 2 more tens |
| 85 + ? = 100 | 15 | make 85 into 90 (add 5), then add 10 |
| 90 + ? = 100 | 10 | 9 tens needs 1 more tens |
| 95 + ? = 100 | 5 | make 95 into 100 (add 5), then add 0 |
The answers start at 5 (for 95) and end at 90 (for 10). Look at the pattern: as the first number goes up by 5, the answer goes down by 5. The pairs 50 and 50 are the only ones where both numbers are the same.
Complements to 100 game idea: making change from a dollar
Make 100 is the same skill as making change from a dollar. A dollar is 100 cents, so if something costs 35¢, the change from $1.00 is 65¢. Try these in a pretend shop: a toy costs 45¢, so how much change from a dollar? 100 − 45 = 55¢, because 45 + 55 = 100. Our counting coins game builds the coin skills, and the making change worksheets practice the same idea on paper.
Make 100 on a hundreds chart and number line
- Hundreds chart: put a counter on 35, then count the squares left to the end of the chart: 65 more. The hundreds chart maker prints one.
- Number line: draw a line from 0 to 100 with tens marked. Jump from 35 to 40, then from 40 to 100 in tens: 5 + 60 = 65.
- Bar model: draw a bar of 100 and split it into 35 and the unknown part, as in the printable chart.
- Base ten blocks: show 3 tens and 5 ones, then trade ones for tens to find how much is needed.
Make 100 word problems
- Mia has 60 stickers and wants 100. How many more does she need? Answer: 40.
- A jar holds 100 beads and has 75 in it. How many more fit? Answer: 25.
- Leo scored 85 points in a game with 100 points possible. How many points did he miss? Answer: 15.
- Ava saved 45¢. How much more makes a dollar? Answer: 55¢.
Where adding to 100 fits at school
| Level | What children are expected to do |
|---|---|
| Grade 2 (US) | Fluently add and subtract within 100 using place value and the relationship between addition and subtraction (2.NBT.B.5) |
| Grade 2 and 3 (US) | Use number bonds to 100 as a mental strategy for adding and finding differences |
| Years 2 to 4 (England) | Recall and use number bonds to 100 as part of mental calculation |
The make 100 game supports these standards. The Common Core grade 2 number and operations in base ten standards give the full text. For paper practice, print the tens and ones worksheets or the hundreds, tens and ones worksheets.
Make 100 game: frequently asked questions
What numbers make 100?
Any two numbers that add up to 100, such as 10 and 90, 25 and 75, or 50 and 50. They are called complements of 100 or number bonds to 100.
How do you find what to add to make 100?
Subtract from 100. Or think in tens: 100 is 10 tens, so find the tens that are missing, and add on the ones left over.
What age is the make 100 game for?
It is aimed at second graders, about ages 7 to 8, who are adding within 100 and learning place value.
Which numbers does the game start from?
Multiples of 5 from 10 to 95, such as 10, 15, 20, 25 up to 90 and 95, so the answers are also multiples of 5.
Is the make 100 game free, and do kids need an account?
Yes, it is free, and no account is needed. Best scores are saved only in the browser on this device.
Does the make 100 game work on phones and tablets?
Yes. Every game is built for touch first and also works with a mouse on a computer.