You bought 12 pencils and pens in total. The pencils cost 1000 won each and the pens cost 1300 won each. You payed 15,000 won for them with no change. Find how many pencils you purchased.
1300 12 [OP_MUL] 15000 [OP_SUB] 1300 1000 [OP_SUB] [OP_DIV]
var_a = 1300
var_b = 12
var_c = var_a * var_b
var_d = 15000
var_e = var_c - var_d
var_f = 1300
var_g = 1000
var_h = var_f - var_g
var_i = var_e / var_h
print(int(var_i))