If you have a problem balancing your checkbook and cannot find the error. Divide the amount your figures are off by 9. If the answer comes out even, then the error is probably a transposition. For instance, if 91 should be 19, the difference is 72. If your figures were off by 72, it is divisible by 9. The answer is 8 but the main idea is to know to look for a transposition. Try this. It really works!