Adding large numbers
Adding large numbers just in your head can be difficult. This method shows how to simplify this process by making all the numbers a multiple of 10. Here is an example:
644 + 238
While these numbers are hard to contend with, rounding them up will make them more manageable. So, 644 becomes 650 and 238 becomes 240.
Now, add 650 and 240 together. The total is 890. To find the answer to the original equation, it must be determined how much we added to the numbers to round them up.
650 – 644 = 6 and 240 – 238 = 2
Now, add 6 and 2 together for a total of 8
To find the answer to the original equation, 8 must be subtracted from the 890.
890 – 8 = 882
So the answer to 644 +238 is 882.
Source: https://resilienteducator.com
