Let's change both numbers so that they have a common denominator. The least common factor of 100 and 10 is 100. That means 100 will be your denominator.
[tex] \frac{87}{100} = \frac{87}{100} [/tex]
[tex] \frac{3 \times 10}{10 \times 10} = \frac{30}{100} [/tex]
Now subtract:
[tex] \frac{87}{100} - \frac{30}{100} = \frac{57}{100} [/tex]
Answer as a fraction is [tex] \frac{57}{100} [/tex]
To change to decimal, divide the numerator by the denominator:
[tex] 57 \div 100 = 0.57 [/tex]
Answer as a decimal is [tex] 0.57 [/tex]
