Only the last digit matters
You add two digits that sit next to each other and write only the last digit of the sum. 7 and 8 make 15, so the answer is 5. You never carry the 1, and you never write a two-digit answer.
The pair then moves one place to the right. The digit on the right of the pair you just did becomes the digit on the left of the next one, so each interior digit is used twice. The first and last digits of a complete row are each used once.
Hold the same pace from the start of the row to the end of it. Choose a pace that lets you keep answering accurately. If you lose your place, take the pair that is marked and carry on from there.
Work one short row
Take the row 7 8 4 9. The first pair is 7 and 8. That makes 15, so the answer is 5.
The pair moves one place right, to 8 and 4. That makes 12, so the answer is 2.
The pair moves again, to 4 and 9. That makes 13, so the answer is 3. The whole row gives 5, then 2, then 3.
Answer one pair
This pair is 9 and 6. Add them, then keep only the last digit of the sum.
Do not carry anything. The answer is always a single digit.
Try it
The marked pair is 9 and 6. What do you type?
- 15
- 5
Show the answer
5
Correct. 9 and 6 make 15, and you keep only the last digit, so you type 5.
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Practice Continuous addition