Question 502970
A rational number can be written as a "ratio" of two numbers, or more plainly as a simple fraction so 
0 = 0/1
0.4 = 4/10
{{{sqrt(16)}}} = 4/1
2 2/3 = 8/3
6.9 = 69/10

those are all rational

{{{sqrt(3)}}} and pi cannot be written as ratios, so they are irrational

Hope that helps