1.
2/3 + 4/5 = 10/15 + 12/15 = 22/15 = 1 7/15,
4/7 * 5/8 = 5/14,
3 - 2/9 : 5/6 = 3 - 2/9 * 6/5 = 3 - 4/15 = 2 15/15 - 4/15 = 2 11/15,
2.
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0 7/12 2/3 1 5/4
2/3 = 8/12, 5/4 = 15/12,
3.
2/5 * 400 = 2 * 80 = 160 детей,
4.
90/120 = 3/4 часть - цветные,
6.
5/12 = 55/132, 5/11 = 60/132, значит:
5/12 < 14/33, 57/132, 29/66, 59/132 < 5/11,
7.
1) 1/3 + 1/2 = 2/6 + 3/6 = 5/6 часть - за 1 и 2 день вместе,
2) 1 - 5/6 = 6/6 - 5/6 = 1/6 - 3 день,
3) 12 : 1/6 = 12 * 6 = 72 стр. - всего в книге
200/2*540+460/10=5446
1 2 4 3
1200-200/(40*5)*5=1150
4 2 1 3
(1200-200/40)*5*5=29875
2 1 3 4
1200-200/40*5*5=75
4 1 2 3