How to calculate eletricity fee based on KWH as below table?

PRICING & TARIFF:

TARIFF CATEGORY RATE PER UNIT
TARIFF D-DOMESTIC
For 1 to 100 units per month 18 sen
For 1 to 150 units per month 18 sen
For 1 to 200 units per month 22 sen
For 1 to 300 units per month 25 sen
For 1 to 400 units per month 27 sen
For 1 to 500 units per month 29.5 sen
For 1 to 700 units per month 30 sen
For 1 to 800 units per month 30.5 sen
For 1 to 1300 units per month 31 sen
For above 1300 units per month 31.5 sen
Minimum monthly charge 5.00

Below is my bill