Discover the Mental Math Secrets to Become a Human Calculator!
Schools taught you a way to do math that works when you have a pen & paper. But the same methods, takes a lot of effort when you have to do math in your head. This is because it uses a lot of your working memory (the short term memory used to complete a mental task).
For example, try to mentally multiply 73,201 x 3. It might take only a few seconds to multiply the individual digits. But if you multiply right to left the way you learnt in school, you will rely on your working memory. You will use it to recall every single digit you calculate to put it back together and get your final answer. You may even find yourself calculating some digits again because you forgot one of the numbers.
The difficulty increases further when you have to multiply larger numbers like 732 x 323. You will have to remember numbers across many steps. Mental arithmetic would be a lot easier to do in your head if you didn't have to remember so many numbers.