You probably do this all the time with time without realising it.
If it’s 11 o’clock and we agree to meet in two hours, you instinctively know I’m talking about 1 o’clock. But what you’ve just done is add two numbers mod(ulus) 12.
In effect your brain added 11+2 to get 13, then took away 12 to make it fit, and came up with the modulus (or remainder) of 1.
Modulus arithmetic is therefore sometimes known as clock arithmetic.
If it’s 11 o’clock and we agree to meet in two hours, you instinctively know I’m talking about 1 o’clock. But what you’ve just done is add two numbers mod(ulus) 12.
In effect your brain added 11+2 to get 13, then took away 12 to make it fit, and came up with the modulus (or remainder) of 1.
Modulus arithmetic is therefore sometimes known as clock arithmetic.