How would you represent the decimal number 143 in 7 bit binary?

First look at the leftmost digit, which represents how many 128s are in the number. There is one 128 in 143, so we mark that as a 1. Then take the remainder of the value - in this case 143-128 = 15, and move on to the second digit, which is 64s. This time there aren't any 64s in 15, so we mark down a 0. By repeating this process, we end up with the binary number of 1001111.