How can I easily double any size number in my head? I'm a software engineer, and I often double numbers especially when doing binary to decimal conversions. When numbers get large, I have trouble doubling a number in my head without using paper. For example, I can double `128` in my head easily because it's common and I have it memorized, but numbers like `183` get more difficult. Is there some clever trick I can use to mentally double any number? I'm probably being idealistic, but it would be nice to have $4$-digit numbers be just as easy to double as $2$-digit numbers.

I usually look for an easy calculation that is close by the original one.

For example:

$2 \times 183 = 2 \times 180 + 6=366$

or

$ 2\times 1481= 2 \times 1500 - 38 = 2960+2$