Bonjour;
a=7/6×7/2-3/2
= 49 /12 -3/2
= 49/12 -3/2*6/6
=49/12 -18/12
=31/12
b=(1/2-3/4)×16/9
= (1/2*2/2 -3/4) *16/9
= (2/4-3/4)*16/9
= -1/4 *16/9
= -16/36 = -8/18 = -4/9
c=1/5-3/10×1/6:1/2
= 1/5 -3/10 *1/6*2
= 1/5 -3/10 *2/6
= 1/5 -6/60
= 1/5 -1/10
= 1/5 *2/2 -1/10
= 2/10-1/10
= 1/10
d=(1/5-3/10):(1/6+1/2)
= (1/5*2/2 -3/10) / 1/6 +1/2*3/3)
= (2/10 -3/10 ) /(1/6 +3/6)
=( -1/10 )/(4/6)
= (-1/10)/(2/3)
= -1/10*3/2
= -3/20
