Читать книгу Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online) - Mark Zegarelli - Страница 15

When you get used to the concept of counting by numbers greater than 1, you can run with it. For example, here’s what counting by threes, fours, and fives looks like:

Counting by a given number is a good way to begin learning the multiplication table for that number, especially for the numbers you’re kind of sketchy on. (In general, people seem to have the most trouble multiplying by 7, but 8 and 9 are also unpopular.)

These types of sequences are also useful for understanding factors and multiples, which you get a look at in Chapter 9.