Bonsoir,
15/90 - 6/90 = 9/90 = 1/10
2a)
6/2=3
=> 2*3
15/3 =5
=> 3*5
2b)
30
c)
1/6 -1/15
= (1*5)/( (6*5) - ( 1* 2) / ( 15*2)
= 5/30 - 2/30
= 3/30 = 1/10
