3/10 of this number minus 8 is 12. Find what 1/5 of this number is.
12 8 [OP_ADD] 3/10 [OP_DIV] 1/5 [OP_MUL]
var_a = 12
var_b = 8
var_c = var_a + var_b
var_d = 0.3
var_e = var_c / var_d
var_f = 0.2
var_g = var_e * var_f
print('{:.2f}'.format(round(var_g+1e-10,2)))