How do you convert a fraction with a nuemartor as 1 and denominator of 5into a decimal?

You can either use long division or make the denomenator a power of 10 (10,100,1000, etc)

because, remember

0.1 = a tenth=1/10

0.01=a hundreth=1/100

so

1/5=x/10

cross multiply

2=x

x/10=tenths

2/10=2 tenths=0.2

answer is 0.2