You may find this hard to believe, but there are people still alive today who once did their mathematical calculations by sliding sticks back and forth. No keypads, no batteries, no LEDs. Just sticks.

Expanding brackets means multiplying everything inside the bracket by the letter or number outside the bracket. For example, in the expression \(3(m + 7)\) both \(m\) and 7 must be multiplied by 3: ...