1/2 = 1*3 / 2*3 = 3/6 = 2/6 + 1/6 = 1/3 + 1/6
1/4 = 1*5 / 4*5 = 5/20 = 4/20 + 1/20 = 1/5 + 1/20
1/6 = 1*7 / 6*7 = 7/42 = 6/42 + 1/42 = 1/7 + 1/42
1/8 = 1*9 / 8*9 = 9/72 = 8/72 + 1/72 = 1/9 + 1/72
15 20 25 30 35 40 все они кратны 5 то есть делятся на 5
А) 1,75 : 1,4 = 175/100 : 140/100 = 175/100 * 100/140 = 175/140 = 1,25
Б) 25,9 : 3,7 = 2590/100 : 370/100 = 2590/100 * 100/370 = 2590/370 = 7
В) 86,1 : 2,46 = 8610/100 : 246/100 = 8610/100 * 100/246 = 8610/246 = 35
Г) 18,4 : 7,36 = 1840/100 : 736/100 = <span>1840/100 * 100/736 = 1840/736 = 2,5</span>
83/15-47/10*8/3-5/9
83/15-376/30-5/9
498/90-1128/90-50/90
-680/90
-7 50/90
-7 5/9