Patterns and Regularity

Word problems name an answer from a rule of repetition or arrangement. Questions naming the color at a given position in a repeating row of colors or symbols, questions counting how many of one color have appeared by that point, repeating numbers, the weekday so many days from today, and rows of numbers growing at even intervals are all worked through.

The writing gives the first four numbers of the row. Put 4 into the expression set up and test whether it matches the fourth number. An expression that multiplied the common difference by the position just as it stands returns a figure one step out here.

Various Word Problems runs for six lessons from here. In How Savings Grow it is not a position in a repetition but the number of times a fixed sum piles up before it reaches a target that gets counted.