What are bigger 0.5 inches or 0.25 inches?

When you have a decimal number, you can always add zeroes without altering the value, so 0.50 is the same as 0.5.

Also if you compare two numbers that have the same unit (here it's inches) that don't have anything before the decimal point, you can compare only what comes after the decimal point. Which leaves you with the question:

What is larger: 50 or 25? 50 is the larger number, so in the original question 0.5 is bigger.

You can also convert to fractions and see which piece of the pie would be bigger.

0.5 = 1/2

0.25 = 1/4

Again half the pie is larger than a quarter of the pie.