Математика 6 класс учебник Мерзляк, Полонский ответы – номер 821

(1 1/12 + 1 1/4) ∙ 1 1/56 + 2 5/8 ∙ 1 3/7 ∙ 1 1/9
1)
1 1/12 + 1 1/4 = 2 + 1/12 + 1∙3/4∙3 = 2 + 1+3/12 = 2 + 4/12 = 2 + 4÷4/12÷4 = 2 1/3
2)
2 1/3 ∙ 1 19/56 = 2∙3+1/3 ∙ 1∙56+19/56 = 7∙75/3∙56 = (7÷7)∙(75÷3)/(3÷3)∙(56÷7) = 1∙25/1∙8 = 28/8
3)
2 5/8 ∙ 1 3/7 ∙ 1 1/9 = 2∙8+5/8 ∙ 1∙7+3/7 ∙ 1∙9+1/9 = 1∙10∙10/8∙7∙9 = (21÷7÷3)∙(10÷2)∙(10÷2)/(8÷2÷2)∙(7÷7)∙(9÷3) = 1∙5∙5/2∙1∙3 = 25/6
4)
25/8 + 25/6 = 25∙3/8∙3 + 25∙4/6∙4 = 75+100/24 = 175/24 = 7 7/24