A books has 8 chapters. You read 3/8 of the book in a week. Use an equation to find how much you have left to read.

Let x = # chapters you have left to read

And you also know that the amount you have left to read is the total number of chapters minus the amount you already read.

The total number of chapters is 8.

The amount you already read is 3/8 * 8 = 3.

Thus:

x = 8 - (3/8 * 8) = 8 - 3 = 5.

You have 5 chapters left to read.