a) 10^3 * a = 4000
1000 * a = 4000
a= 4000 : 1000
a= 4
b) a : 10^2 = 53
a : 100 = 53
a= 53*100
a= 5300
c) 10^2 * a = 70000
100 * a = 70000
a= 70000: 100
a= 700
d) a : 10 = 2^5
a : 10 = 32
a = 32*10
a= 320
e) 100 : a = 2^2
100 : a = 4
a = 100 : 4
a= 25
f) a : 10^3 = 9
a : 1000 = 9
a = 9*1000
a= 9000
