Adding and taking away
A part-whole diagram works for adding and for taking away. If you know the two parts, add them to find the whole: 5 + 3 = 8. If you know the whole and one part, take the part away to find the other part: 8 − 3 = 5. Number bonds help you with both. You can take away a smaller number from a larger number, or the same number. Look for patterns too. Start at 10 and take away 2 again and again: 10 − 2 = 8, 8 − 2 = 6, 6 − 2 = 4. The answers are even numbers, going down in twos.
Bond posters: choose the number 9 and use counters to find all its number bonds, such as 2 + 7 and 4 + 5. For each bond, also write a take-away sentence, like 9 − 2 = 7. Then play the pattern game: put 10 counters out and take away 2 at a time, saying each sentence. What do you notice about the answers?