This section has three-digit multiplicands, but only one-digit multipliers. The sum can be up to four digits. If you're like me, you might struggle with this initially. One way I sometimes try difficult or lengthy multiplication problems is to multiply it by a multiplier I find simpler - often 10, or 5, which is half of 10 - and then add or subtract the number as many times as the difference between that and the real multiplier, until I get it to the right product. If you have a good working memory and recall all the variables, however, you might find it better to work the problem out without these intermediate steps.