Binary numbers and Roman numerals
Read and write binary numbers with the place values 1, 2, 4, 8, 16 and compare Roman numerals with our place value system.
- Germany: grade 5
Guide
In the decimal system we bundle in tens. In the binary system (Dualsystem) we bundle in twos. There are only two digits, 0 and 1. The place values are 1, 2, 4, 8, 16 and so on: each is twice the one on its right.
To read a binary number, add the place values that have a 1. For 1011₂ these are 8, 2 and 1, so the number is 11. To write a number in binary, find the biggest place value that fits and work down.
Roman numerals use the letters I, V, X, L, C, D, M. A smaller letter before a bigger one is subtracted (IV = 4, CM = 900). Roman numerals are no place value system: this makes calculating with them hard.
The place values are shown as a row of numbers above. The binary number is typed as its digits: 1101 means the digits one, one, zero, one.