Răspuns:
2 × 43 × 5 × 10 = (2 × 5) × 10 × 43 = 100 × 43 = 4300
6 × 19 × 5 = (6 × 5) × 19 = 30 × 19 = 570
2 × 13 × 50 = (2 × 50) × 13 = 100 × 13 = 1300
2 × 8 × 100 × 5 = (2 × 5) × 100 × 8 = 1000 × 8 = 8000
12 × 147 × 10 = (10 + 2) × 147 × 10 = (10 × 147 × 10) + (2 × 147 × 10) = 14700 + 2940 = 17640 (fără a folosi distributivitatea, nu poți grupa convenabil)
15 × 16 × 2 = (15 × 2) × 16 = 30 × 16 = 480
2 × 25 × 2 × 60 = 100 × 60 = 6000
4 × 68 × 25 × 10 = (4 × 25 × 10) × 68 = 1000 × 68 = 68000
