The numerator tells you how many pieces of pie you’re going to get to eat. If the fraction is 1/2, that means you cut the pie into two equal size pieces and then choose one of the pieces: you get one out of two pieces, or half the pie. If the fraction is 3/6, that means you cut the pie into six equal pieces and then choose three of the pieces. You eat three out of six pieces, or, again, half of the pie.
To add two fractions together, you need to make sure the denominators (the number on the bottom) are the same, and then add the two numerators together. So 1/3 + 2/3 = 3/3 (that’s 1). To multiply two fractions, you just multiply the two numerators (the top numbers) and put that on the top, and multiply the two denominators (the bottom numbers) and put that on the bottom. So 1/3 x 2/3 = 2/9.