How to Multiply Using the Distributive Property

これさえ読めば安心! How to Multiply Using the Distributive Propertyの対策を順番に解説します。

Last week, I was baking cookies. The recipe called for 2 cups of flour, but I needed to triple it for a bake sale. The recipe also said “add ½ cup of sugar per batch.” I stood there, oven mitt in hand, and realized: 3 × (2 + 0.5) = (3×2) + (3×0.5). Flour: 6 cups. Sugar: 1.5 cups. Easy.

I didn’t even need to think about it—the property just works because it mirrors how we naturally break things down. We all do this already; we just don’t give it a fancy name.

And my cookies? They turned out perfect. Coincidence? I think not. Math makes better bakers.

Blog — Mashup Math

The One Rule You Can’t Forget

Here’s the warm hug of the distributive property: it always works for addition and subtraction inside the parentheses. But it won’t work for multiplication or division inside—so don’t try to distribute into a (3 × 4). That’s a different beast.

Think of the parentheses as a VIP room. The number outside is the bouncer. The bouncer can only hand out access passes to each person (the added or subtracted numbers) individually. He can’t break apart a married couple (a product) inside. Silly analogy, but it sticks.

Stick to the rule, and you’ll never mess it up.