1. 101²52²1003² 98²79² Calculer sans poser dopération et sans calculatrice : 997² 99 10132 281003 997 105² - 95²52² - 48²31² - 29²

2. (100+1)² 101² = = 10 000+200+1 100² 2 100 1 1² = 10 201

3. (50 + 2)² 52² = = 2 500+ 200+ 4 50² 2 50 2 2² = 2 704

4. (1000+3)² 1003² = = 1000 000 +6 000 + 9 1000² 2 1 000 3 3² = 1 006 009

5. (100-2)² 98² = = 10 000- 400+ 4 100² 2 100 2 2² = 9 604

6. (80 - 1)² 79² = = 6 400- 160+ 1 80² 2 80 1 1² = 6 241

7. (1000-3)² 997² = = 1000 000- 6 000+ 9 1000² 2 1 000 3 3² = 994 009

8. (100 + 1)(100 - 1) = 100² 1² 10 0001- 99 101 = = 9 999

9. (30 + 2)(30 - 2) = 30² 2² 9004- 32 28 = = 896

10. (1000 + 3)(1000 - 3) = 1000² 3² 1 000 0009- 1003 997 = = 999 991

11. 105² - 95² = (105 +95) (105-95) = 200 10 = 2000

12. 52² - 48² = (52 + 48) (52 - 48) = 100 4 = 400

13. 31² - 29² = (31 + 29) (31 - 29) = 60 2 = 120