You can find speed tests online or in your local school supply store. Typically, there will be 50 problems on a single sheet that you will work through. Work as fast as you can to finish and then go back to check your work. The worksheets should take you less than 3 minutes per test page. Set a timer to stick to the 3-minute limit. Aim for accuracy above time, but eventually you will only to have to focus on how fast you can get the right answer out.
Rather than finding multiplication tables to print out, create your own. The practice of writing the table out will start to work the numbers into your memory even sooner. Write them out at least 7 times before sticking to 1 of your sheets to study. Keep working on the tables until you just remember what 6 x 13 is, for example. You should not have to work out the math for any of the 256 combinations. You can find multiplication speed tests similar to the addition and subtraction ones as well online and in school supply stores. After reviewing the tables sufficiently, work up to the timed tests.
Having this type of recall will also help you to recognize when a number won’t be evenly divisible. For example, you might see 127 / 14 and remember that this is almost the even division of 126 / 14 = 9. Since the numerator is slightly off, you will know to resort to working out the problem. Knowing that 127 is larger than 14 x 9 will help you to immediately realize that the answer is going to be slightly larger than 9!
Instead of dealing with writing down the multiplication and work right-to-left, you can realize that you’re looking for 125 x (10 + 5) = (125 x 10) + (125 x 5) = (125 x 10) + (125 x 10 / 2). By breaking the problem down to one simple calculation of 125 x 10, one division by 2, and one addition, you avoid a trickier multiplication. Always look for ways to use simpler calculations or memorized multiplication tables, for instance, to simplify a harder calculation. Understanding these component parts can then be applied to leaving a 15% tip, for example, and all you have to do is move some decimal places afterward.
Challenge yourself to work on areas that you notice you struggle in. If fractions tend to give you a hang up when calculating, spend a week or two just doing fraction calculations. Even just looking at multiplication tables or worked out problems is beneficial. Eventually, you will start to notice patterns and new ways to deconstruct problems you didn’t see before.
Hearing yourself say a number creates another mental copy of the number in your working memory. With an auditory and visual copy of the number, it becomes easier to recall as you’re calculating.
Although fingers can be a quick way to hold a number aside during a calculation, try to rely on the visual memory or even auditory memory instead. Testing yourself by not relying on a calculator or even writing the numbers down will help with your working memory, number recall, and even visual/spatial skills.
