First thought: grams is a measure of weight, ounces is a measure of volume, well OK, weight in some cases.
An ounce of volume equals an ounce of weight ONLY for water or anything else with a specific weight of 1
75 grams is equal to 2.6455 ounces of weight, not volume !(28.3495231 grams/1 ounce (weight))
Granulated sugar has a specific weight of, approximately, 0.849, so 2.6455 ounces (weight) will be approximately 3.11 ounces (volume), so I would use 3 ounces (volume) or 6 tablespoons or 18 teaspoons.
Flour is a lot trickier, the specific weight varies with the variety, the fineness, whether it is scooped, sifted, etc. Generally, if it is gently spooned into a measuring cup and then struck off with a straight edge, the specific weight is very close to 0.5625, but it can be as high as 0.75 if it is somewhat packed. So, for 75 grams of flour which equals the same 2.6455 ounces (weight), the approximate volume would be 4.7 ounces (volume) in the first case to 3.53 in the second. I'd figure the first case, 4.7 ounces (volume) and I'd probably round off to 1/2 cup + 1 1/2 tablespoons.
The simple solution? Buy a digital kitchen scale that has a grams/ounces conversion and weight everything
You can use Food Densities (weight/volume relationships) to find the specific weights as well