Unit 1: positive numbers and negative numbers. Whether there is a test center depends mainly on your time. Unit 2: Interest rate = interest ÷ principal × percentage. Corresponding quantity = unit 1 × corresponding score. Unit 1 = corresponding quantity ÷ corresponding score. Unit 3: V-pillar = R? H=sh .v cone = 1/3 pie R? H = 1/3SH = 1/3V column. Unit 4: Scale = Distance on Map: Actual Distance. Distance on the map = actual distance × scale. Actual distance = distance on map/scale. (Hope to adopt)