Answer: 1/4 cup more (or half of the 1/2 cup)
Step-by-step explanation: If you need 3/4 cups of sugar but only have 1/2 cup of sugar, then you have 2/4 cups of sugar. This is because we have to convert the 1/2 cup into fourths. You can do this by: 1/2 multiplied by 2 (to equal 4). What you do to the denominator, you do to the numerator. So, 2/2 multiplied by 1/2 gives us 2/4. Now, to get to 3/4, you only need 1/4 cup of sugar. If it helps, instead of thinking with fractions, try to imagine cooking. Its easier to think of converting measuring cups in cooking then to remember all the math behind conversions. Hope this helped! :)