Four can be equal to five just take a look to this theorm that has proved that four is equal to five according to Minestine(will be scientist soon).

-20 = -20

16-36 =  25-45

4ˆ2 - 9*4 = 5ˆ2 - 9*5

4ˆ2 - 9*4 + 81/4 = 5ˆ2 - 9*5 + 81/4

(4-9/2)ˆ2 = (5-9/2)ˆ2

4 - 9/2 = 5 - 9/2

4 = 5 —> Proved