math.md

title	actions	material
Math Operations	checkAnswer hints	editor language startingCode answer sol pragma solidity >=0.5.0 <0.6.0; contract ZombieFactory { uint dnaDigits = 16; //start here } pragma solidity >=0.5.0 <0.6.0; contract ZombieFactory { uint dnaDigits = 16; uint dnaModulus = 10 ** dnaDigits; }

Math in Solidity is pretty straightforward. The following operations are the same as in most programming languages:

• Addition: x + y
• Subtraction: x - y,
• Multiplication: x * y
• Division: x / y
• Modulus / remainder: x % y (for example, 13 % 5 is 3, because if you divide 5 into 13, 3 is the remainder)

Solidity also supports an exponential operator (i.e. "x to the power of y", x^y):

uint x = 5 ** 2; // equal to 5^2 = 25

Put it to the test

To make sure our Zombie's DNA is only 16 characters, let's make another uint equal to 10^16. That way we can later use the modulus operator % to shorten an integer to 16 digits.

1. Create a uint named dnaModulus, and set it equal to 10 to the power of dnaDigits.