When you multiply a number by 7 and then add 21.28, you get 50.68. Find a number.
50.68 21.28 [OP_SUB] 7 [OP_DIV]
var_a = 50.68
var_b = 21.28
var_c = var_a - var_b
var_d = 7
var_e = var_c / var_d
print('{:.2f}'.format(round(var_e+1e-10,2)))