Hexadecimal and binary together

This lesson practises division by 16 once more with bigger numbers, and adds a habit: always check. Convert 4000: 4000 ÷ 16 = 250 remainder 0; 250 ÷ 16 = 15 remainder 10, written A; 15 ÷ 16 = 0 remainder 15, written F. Reading upwards gives (FA0)₁₆. The first remainder, 0, is a real digit and must be written: without it the answer would be FA, which is only 250. To check, multiply back: 15×256 + 10×16 + 0 = 3840 + 160 + 0 = 4000. If you do not get the number you started with, look for the mistake in the remainders, in their order or in the letters. Also remember that a hexadecimal answer may use only digits: (2328)₁₆ looks like an ordinary number but is not one, and the small 16 tells which system it is written in.