Dividing numbers that = decimals

[Kinma]

If my previous post is unclear, in the past I wrote a lot about division and also about negative remainders:

Making two digit (or more) mental division easier by using negative remainders

In a chat with Tiger, the following came up: Work with both positive and negative remainders. Why would you do this? Well, it keeps the digits you work with down to 0-5, which is easier than to work with 0-9. What I mean is, that for example if you need to divide by 42, you have probably learned that if the next digit is 9 you would first need to work out 42X9 and then subtract. While this is a consistent system and doable on paper, this is difficult to do in your head. In my way of calculat…

Mental Calculation - Division - Resources?

I’ll give you another way of dividing. One that is less well known and is interesting for dividing by multiple digits. An example will make it clear: Let’s say we need to know 100 / 21. What we do is we divide by 20, easy peasy, and subtract a correction in the next step. 100 / 20 is 5. However, this leaves us with no remainder and in the next step we are going to subtract something, which takes us into negative territory. This is to be avoided, so we will use 4 instead of 5: 100 / 20 = 4 …