Since it is rather annoying to write out many ones and zeroes, there is a shorthand way of writing binary, called hexadecimal. Each four binary bits are encoded by a single hexadecimal digit. Here is a table showing what each hexadecimal digit stands for.
To write hexadecimal numbers in assembly language, we append the number with an h and prepend it with a 0. So now we have a third way of writing the number 214 in assembly language. It is 0D6h.
We can also specify numbers to be moved into registers, in hexadecimal.
Of course hexadecimal is base 16, where there are 16 different possibilities for each digit (0-F), and where each place corresponds to a power of 16.
E.g. 045C3h corresponds to the decimal number 4x16^3 + 5x16^2 + 12x16^1 + 3x16^0 = 16384 + 1280 + 192 + 3 = 17859.