It took 13/5 tins of paint to paint one wooden board. Another identical wooden plank is painted and the amount of paint remaining is 9/7 tins. Find how many cans of paint were in the beginning.
9/7 13/5 [OP_ADD] 13/5 [OP_ADD]
var_a = 1.2857142857142858
var_b = 2.6
var_c = var_a + var_b
var_d = 2.6
var_e = var_c + var_d
print('{:.2f}'.format(round(var_e+1e-10,2)))