1. Estimer La somme et la différence de grands nombres

2. Estimate The sum and difference of big numbers

3. En quelques secondes, est-ce que la réponse est bonne ou non? 694 348 +214 492 672 819 Comment le sais-tu si rapidement???

4. Within a second, tell me if the answer is right or wrong 694 348 +214 492 672 819 How can you tell very quickly???

5. OUI: tu as estimé la somme Tu arrondis chaque nombre puis tu additionnes mentalement. Ex: 56…60 + 39… +40 … 100

6. YES: You estimated the sum! You rounded off each number and you added them. Ex: 56…60 + 39… +40 … 100

7. Méthode 347 = environs 350 +223= environs 200 (570) = environs 550 938= environs 900 - 234= environs 200 (704)= environs 700

8. Method 347 = around 350 +223= around 200 (570) = around 550 938= around 900 - 234= around 200 (704)= around 700

9. Avec un partenaire: estime 1) 534 + 928 = 2) 382 + 402 = 3) 7402 + 490 = 4) 736 - 508 = 5) 9819 - 5729 =

10. With a partner: estimate 1) 534 + 928 = 2) 382 + 402 = 3) 7402 + 490 = 4) 736 - 508 = 5) 9819 - 5729 =

11. Individuellement: estime a) 4573 + 5270 = b) 2935 + 2738 = c) 27385 + 20238 = d) 739487 + 27395 = a) 20589 – 16123 = b) 124857 – 23047 = c) 42934 – 14237 = d) 129 – 123 =

12. Individually: estimate a) 4573 + 5270 = b) 2935 + 2738 = c) 27385 + 20238 = d) 739487 + 27395 = a) 20589 – 16123 = b) 124857 – 23047 = c) 42934 – 14237 = d) 129 – 123 =