Fraction to Decimal:
Divide the numerator (upper number) by the denominator (bottom number) on your calculator. Whatever number you get would be your decimal.
Decimal to Percent:
Take your decimal and use your calculator to multiply it by 100. Whatever number you get would be your percent. However, since it is a percent, you need to include the percentage unit.
Demonstration:
1/4 = 0.25
0.25 * 100(%) = 25%