7/20*9+12*7/36+1 8/15 :4+3/5:4 1/2 решите пример по действиям заблаговременно спасибо

1) 7/20 * 9 = 63/20

2) 12 * 7/36 = 84/36 = 7/3

3) 1 8/15 / 4 = 23/15 / 4 = 23/60

4) 3/8 / 4 1/2 = 3/8 / 9/2 = 1/12

5) 63/20 + 7/3 + 23/60 + 1/12 = 189/60 + 140/60 + 23/60 + 5/60 = 357/60 = 5 57/60 = 5 19/20

1. (7/20)*9=63/20.

2. 12*7/36=7/3.

3. 1/:4=(23/15):4=23/60.

4. (3/5):4/=(3/5):(9/2)=3*2/(5*9)=2/15.

5. 63/20+7/3+23/60+2/15=(63*3+7*20+23*1+2*4)/60=

=(189+140+23+8)/60=360/60=6.