You mistakenly subtracted 13/5 from a number instead of adding 13/5 and got 9/7. How much is it when calculated correctly?
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)))