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