help with these if statements

[Keeelooo]

a)Display “Great Job” when gradeis 90 or greater.
b)Display “Error” when number is less than 20 or greater than 50
c)Output “There are <m> meters left.” if metersis not equal to zero. The placeholder <m> represents the value of the variable meters.
d)Calculate averageCost as totalCost divided by numItems,if numItemsis greater than zero. Otherwise display the message “No items purchased”

[Insectoid]

You need to demonstrate that you have put some effort into solving these problems before we will help you. We will not do your homework.