1. La multiplication grecque

2. 56  23 = 1 288 5 6  5  2 = 10 6  2 = 12 1 1 2 1 0 2 5  3 = 15 3 1 1 2 6  3 = 18 5 8 8 8 1 + 0 + 1 = 2 5 + 1 + 2 = 8

3. 3457  609 = 2 105 313 6 + 5 = 11 3 4 5 7  6 + 4 + 2 + 1 = 13 1 1 1 1 3 2 1 2 4 6 1 4 0 8 2 7 + 3 + 4 + 1 = 15 0 0 0 0 1 0 0 0 0 0 2 + 4 + 3 + 1 = 10 2 4 3 6 9 0 7 6 5 3 8 + 2 + 1 = 11 5 3 3 1 1 + 1 = 2