Doubling with no carries

Doubling is a very efficient math technique that is often under utilized. If you can double you can add, subtract, multiply and divide certain numbers easily. When learning our addition facts we often pick up doubles easily. Adding the digits to themselves seems fun.

One great thing about doubling is that there are only 10 numbers you need to be able to double. If you can double those 10 numbers, you can double anything. WooHoo :)

Ta Da! You have just doubled everything there is to double. Ever.

So let us get started doubling...

Let's say you have the number 23...

Step 1: Double the first digit, so 2 doubled is 4

Step 2: Double the next digit, so 3 doubled is 6

Great, our answer is 46

Let's try another one, how about doubling 324

Step 1: Double the first digit, so 3 doubled is 6

Step 2: Double the next digit(s), so 2 doubled is 4 and 4 doubled is 8

Great, our answer is 648, easy right?


Now here are some practice problems for you to have fun with.

    14          32          12           42          20

  130        243        212        732        524

9142      7314      1310      7143      6421

2102      2011      5434      6023      9331