To solve this problem, we need to set up a proportion. Let x be the unknown amount of grams of sugar that will be used for 7 cakes (what we are trying to figure out). 5/150 = 7/x Now, to simplify this equation, we need to use cross-products, which is setting the products of the opposite numerator and denominator equal to one another. If done correctly, it should look like this: (5)(x) = (150)(7) When we simplify both sides of the equation by multiplication, we get: 5x = 1050 Finally, we have to divide both sides of the equation by 5 to get our variable, x, alone on the left side of the equation. x = 210 Therefore, if you use 150g of sugar for 5 cakes, you must use 210g of sugar for 7. Hope this helps! :)