7,25 * 11 1/8 - 6 1/8 - 6 1/4 * 11,25 = 4,21875,
1) 7,25 * 11 1/8 = 725/100 * 89/8 = 29/4 * 89/8 = 2581/32 = 80,65625
(или = 80 65625/100000),
2) 6 1/4 * 11,25 = 25/4 * 1125/100 = 25/4 * 45/4 = 1125/16 = 70,3125 (или = 70 3125/10000),
3) 80 65625/100000 - 6 1/8 - 70 3125/10000 = 80 65625/100000 -
- 6 12500/100000 - 70 31250/100000 = 4 21875/100000,
(или 80,65625 - 6,125 - 70,3125 = 4,21875