Hi there! :D
Let's simplify this together first!
20/30
We can divide both sides by 5 since both are divisible by 5.
You would divide both sides by 5.
20÷5= 4
30÷5=6
4/6, we can divide it by 2 to get: 2/3 <== that is the simplest fraction.
Nicholas' error was that he divided 20 by 5 and then 30 by 6. You would divide both by 5. You would change:
30÷6=5 to 30÷5=6
I hope this helps!
~kaikers