Block Adder: Sums to 10

How to play Sums to 10

1. A sum waits above the board, such as 6 + 2 or 8 − 3. Work out the answer.
2. Tap a column to drop it next to a block with that answer, below it or beside it. The sum and the answer disappear together.
3. If it lands anywhere else, the sum turns into its answer and becomes a number block for the next sums.
4. The game ends when a column is full to the top.

Stuck? Press Hint to see a column where your block makes a bond. Every bond you make, the adder above the board eats it and grows one block longer.

Easy gives more blocks that fit somewhere, Tricky fewer. Dots show each number as a frame of dots: count the empty ones to find the partner.

For parents and teachers

Sums to 10 practises addition and subtraction facts within 10, with every answer from 0 to 10. Seeing 4 + 3 and 9 − 2 land on the same 7 also shows that adding and taking away are linked. Fluency within 10 is a grade 1 standard in the US Common Core (1.OA.C.6); in England’s national curriculum, Year 1 children add and subtract one-digit numbers.

A guide: ages 6 to 7. Dots on the number blocks help with counting on Easy.

The Block Adder games

• Make 5: Find two blocks that add up to 5, like 2 and 3.
• Make 10: Find two blocks that add up to 10, like 3 and 7.
• Make 20: Find two blocks that add up to 20, like 12 and 8.
• Make 100: Find two tens that add up to 100, like 30 and 70.
• Sums to 10: Drop each sum on its answer: 4 + 3 goes on a 7.
• Sums to 20: Drop each sum on its answer: 12 − 3 goes on a 9.

Questions

Can an answer be 0?

Yes: a sum like 5 − 5 has the answer 0, and a 0 block is a real block on the board. Answers are never below 0.

Why does a sum turn into a number?

So the board fills with answers to aim for. A sum that finds no matching answer stays on the board as its answer, ready for a later sum.

Is it safe for children?

Block Adder has no ads, no chat, no sign-up and no tracking. Nothing your child does is sent anywhere: the game in progress, the best scores and the statistics are kept only in this browser.

Does it work on a phone or tablet?

Yes. Tap a column to drop the block there. It fits a phone held upright, and it works with a mouse or the keyboard on a computer.

Keyboard

More to play

• All kids games