To find out which fraction is the greatest - what I like to do is convert the fraction to the percentage form.
To change a fraction into the percentage form, you have to multiply the fraction by 100, which is the commonly used numerical number.
The problems for both of the fractions would look like:
2/5 × 100 and 3/10 × 100
To solve both of those, you basically just have to focus on the numerator (the top number of the fraction) and what you are multiplying it by, which in this case is by 100. We have to multiply the numerator by the whole number (100) and then find what multiplies with the denominator to get the result of the numerator.
We have our first fraction turned into the percentage form, so 2/5 = 40%.
3/10 as a percentage is 30%.
Looking at the percentages for 2/5 and 3/10, the greatest one out of the two is
2/5, which is 40%.