Beginning algebra: writing equations for word problems

We look at four different word problems and write an equation for each. The first one involves the perimeter of a parallelogram. The second, area of a two-part rectangle. The third one has to do with the ages of two people — we know one is four times as old as the other, and 40 years older than the other. In the last problem, we're given the aspect ratio and the perimeter of a rectangle, and the task is to find the side lengths.

For each problem, write a fairly simple linear equation and then solve the equation. I also solve some problems without the equation first — so you can see how the mental math or bar diagram solution steps match with the steps of solving the equation.

See also

Word problems and equations, part 2 — video lesson

Math Mammoth Grade 7 curriculum (pre-algebra)

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