Question

Решить. заранее . найдите значение выражений: 1) (4целых1/5-2целых3/4)×2целых2/19; 2) (5целых6/7+3целых5/21)×2целых1/10 3) (7целых5/12-3целых1/6)×2целых2/17;

Answer 1

1) (4 1/5 - 2 3/4)*2 2/19 = (4 4/20 - 2 15/20)*2 2/19 = (3 24/20 - 2 15/20)*2 2/19=
= 1 9/20 * 2 2/19 = 29/20 * 40/19 = 1,160/380 = 3 20/380 = 3 1/19
2)(5 6/7 + 3 5/21)* 2 1/10=(5 18/21 + 3 5/21)* 2 1/10 = 8 23/21 * 2 1/10 = 192/21*
*21/10 =4,032/210 = 19 42/210 = 19 6/30 = 19 1/5
3)(7 5/12 - 3 1/6)*2 2/17 = (7 5/12 - 3 2/12)*2 2/17 = 4 3/12 * 2 2/17 = 51/12 * 36/17=1,836/204= 9

Answer 2

(21/5-11/4)×40/19=(4×21-5×11)/20×40/19=29/20×40/19=(2×29)/19=3 целых 1/19.
2)(41/7+68/21)×21/10=(3×41+68)/21×21/10=191/21×68/21=
=191/10=19 целых 1/10
3)(89/12-19/6)×36/17=(89-2×19)/12×36/17=51/12×36/17 =3×3=9.