计算下面各题,能简算的要简算. (1)( 1 5 + 1 3 )×15 (2) 4 7 × 5 9 + 3 7 × 5 9 (3) 1 3 × 5 16 × 3 5 (4)2.5×97×0.4 (5)1.25×97×8 (6)1.25×32×2.5×97 (7)0.36×101 (8)0.36×98 (9) 5 7 - 5 9 × 5 7 (10) 2 9 + 7 16 × 2 9 (11) 1 4 + 3 4 × 2 7 (12) 2 5 - 2 5 × 3 8 (13)90× 4 91 (14)86× 2 91 (15) 7 5 × 2 3 - 2 5 × 2 3 (16)0.36×101-0.36 (17)0.36×99+0.36 (18) 13 20 × 15 26 - 2 9 .