Long Division. There are different methods for dividing multi-digit numbers (long division). One way is a combination of estimation/ trial and error and multiplication. There is also a commonly used algorithmic method that is well explained and illustrated here at mathisfun.com.
Skip counting is counting at intervals of whichever number you choose. For example, if I was to skip count by 7 I would count, 7, 14, 21… and so on. Using this method you can do single digit multiplication with ease. Say the teacher asks you to multiply 4 x 7 = __. You simply skip count 7’s, 4 times, 7, 14, 21, 28. The answer to 4 x 7 = 28.