1) count and mark so that you will have 50 blocks to work with. Shade 19 of those blocks. This will represent your fraction. To get the % divide 19/50= 0.38 move the decimal to the right two places and you will have 38%.
2) do the same count and mark off 20 blocks and shade 13. This represents the fraction. Divide 13/20 = 0.65. Move the decimal two places to the right and you will have 65%.