Creating Code With If...else If...else Statement?

I am thinking of how to write the code for below scenario to create a simple online customize calculator:There is 1 box which allow us to enter any number=x (representing amount of money). So whenever we entered a number in the box and click "CALCULATE" buton below the box,there will be 3 results generated in 3 boxes below it based on the set of of rules i.e.

1. if the amount entered is <21,000

Result 1 = 1.5%*x*12
Result 2 = 1.5%*x*48
Result 3 = 1.5%*x*120

2. if the amount entered is >=21,000 and <210,000

Result 1 = 1.8%*x*12
Result 2 = 1.8%*x*48
Result 3 = 1.8%*x*120

3. if the amount entered is >=210,000

Result 1 = 2.2%*x*12
Result 2 = 2.2%*x*48
Result 3 = 2.2%*x*120

I understand that this code will involve If...else if...else Statement..