c urgent svp soustractions. multiplication. addition

4/5+1/5x -1/2
4/5 -1/10
8/10 -1/10
= 7/10

3/4x(1/6 + -5/12)
3/4(2/12 -5/12)
3/4 (-3/12)
3/4(-1/4)
-3/16

3/2 -7/3 : 5
3/2 -7/3x1/5
3/2 - 7/15
45/30 -14/30
31/30

3x5  / 4x5
15/20
=3/4



3x20x5  / 15 x-10
3x10x2x5 / 3x5x10
= -2

-64 x 77 x35  / 16 x-14x36
-16x4  x 7x11x35 / 16 -7x2 x36
4  x 11 x35/   -2x36
2x11x35  / -36
770 / -36
-385/3