Why you can use a subtraction to solve a division problem

Question : Why you can use a subtraction when solving a division problem.

=> subtraction is one way of solving the given division problem for example
=> 100 / 10 , this means that how many 10s are there in 100.
Other way of solving this is through subtraction:
=> 100 – 10 = 90 (1)
=> 90 – 10 = 80 (2)
=> 80 – 10 = 70 (3)
=> 70 – 10 = 60 (4)
=> 60 – 10 = 50 (5)
=> 50 – 10 = 40 (6)
=> 40 – 10 = 30 (7)
=> 30 – 10 = 20 (8)
=> 20 – 10 = 10 (9)
=> 10 – 10 = 0 (10)
See that we still have the same number even if we do the subtraction or division.

Ican't solve. your equation is impossible. you can't have two equal signs.