31. Percent Change

new − old old × 100

Interest

Money earned or paid. Simple interest: 𝐼 = 𝑝 𝑟 𝑡

Proportion

Two ratios that are equal. Example: 𝑎 𝑏 = 𝑐 𝑑

34. Unit Rate

Amount per 1 unit. Example: $12 for 3 apples → $4 per apple.

Exponent

shows repeated multiplication. Example: 3 4 = 3 ⋅ 3 ⋅ 3 ⋅ 3