Improving your math skills is an important step you can take in order to enhance your business life as well as your personal life.
There are many diferent tips you can learn that will help you add and subtract any numbers that you may choose without the aid of a calculator.
Method #1- Adding Whole Numbers
Most numbers can actually be added in your head if you can visualize them. Let’s take for example 49+87. One of the easiest and quickest methods for adding these two numbers, without the benefit of a calculator or pencil and paper, is to add them up in your head. How do we do this? We simply separate the numbers and then add the separate parts together to make a sum. Separate the 87 into 80 and 7, and separate the 49 into 40 and 9. Now, add the highest numbers which would be 80 and 40.
The answer comes to 120. Now add the 9 to the 120; this equals 129. Lastly, add the 7 to 129, and the sum is 136. This even works when you are adding two numbers such as 88 and 99. Using a pencil and paper, you would need to carry numbers. You can do this in your head without carrying any numbers from the right column to the left column. This might seem difficult at first, but as long as you can visualize the numbers in your mind and keep track of the subtotals, you are on your way to learning a simple, yet very effective system for learning how to add numbers.
Method #2- Subtracting Whole Numbers
Subtracting is a little trickier, but it can still be done in your head also. Try to subtract 455 from 1,000. That’s alot to remember, isn’t it?
Since you have probably learned the usual method of subtracting on paper- that is, writing down the 1,000 and then placing a minus sign at the left of the problem and then writing down the 455, drawing a line underneath, and beginning to subtract starting at the farthest number on the right side you are probably thinking that there is no way you can put all of those numbers in your head and remember them! Well, there’s good news- you don’t have to! To subtract these numbers in your head, think of it like a cashier making change. Simply add instead of subtracting.
We do this by adding numbers onto the 455 until we reach 1,000. 455 plus 5 equals 460; 460 plus 40 equals 500; 500 plus 500 equal 1,000. Then we add the numbers 5+40+500 and come up with the sum of 545.
Or, you can take the 455, add 500 to make 955, add 40, and then 5 to come up with 1,000. There are several ways you can add the lowest number or the number that you wish to actually subtract from the highest number to other numbers to come up with the 1,000.