Another method to convert to binary, which I often use because I find it a bit faster is by subtracting, instead of dividing. In order to use this method, it is important to memorize the essential numbers in the binary tree, though.

For the example given of 173, we need to remember which possible numbers in the binary tree we can subtract from it, from the highest possible number, and than procede subtracting.

Let’s use this: 256, 128, 64, 32, 16, 8, 4, 2, 1

In this case, from 173, we can subtract 128, which leave us with 45.

Subtract 32, leaving us with 13.

Subtract 8, leaving us with 5.

Subtract 4, leaving us with 1.

Subtract 1, leaving us with 0.

We then “light up” the numbers we subtracted in the binary system, from 0 to 1.

So 173 = 10101101