AB: Vorteilhaftes Addieren und Subtrahieren
1.
Berechne den Wert jedes Zahlterms auf vorteilhafte Weise.
| a) | 15 + 17 + 13 = |
= 15 + 17 + 13
= 15 + 30 = 45 |
| b) | 25 + 336 - 36 = |
= 25 + 336 - 36
= 25 + 300 = 325 |
| c) | 58 + 41 + 19 + 2 = |
= 58 + 41 + 19 + 2
= 58 + 2 + 41 + 19 = 60 + 60 = 120 |
| d) | 52 + 54 - 12 + 6 = |
= 52 - 12 + 54 + 6
= 40 + 60 = 100 |
| e) | 856 + 361 - 16 - 5 - 1 = |
= 856 - 16 + 361 - 1 - 5
= 840 + 360 - 5 = 800 + 300 + 40 + 60 - 5 = 1100 + 100 - 5 = 1100 + 95 = 1195 |
| f) | 346 - 9 - 3 - 7 + 19 = |
= 346 + 19 - 9 - 3 - 7
= 346 + 10 - 3 - 7 = 346 + 7 - 7 = 346 + 0 = 346 |
| g) | 46 + 84 - 34 + 4 - 10 |
= 46 + 4 - 10 + 84 - 34
= 50 - 10 + 50 = 40 + 50 = 90 |