tolong bantu 1-4 pakai caranya ya di bawah please!!!

a) 2/5 x 15/6 = 30/30 = 1
b) 1 1/2 x 3/4 = 3/2 x 3/4 = 9/8
c) 2/3 x 6/8 x 16/32 = 192/768 = 1/4
d) 1 1/2 x 2 2/3 x 3 3/4 = 3/2 x 8/3 x 15/4 = 360/24 = 15