= 6, 15 + (-6 + 1/30) + 3/20
= 6, 15 + (-6 + 1/30) + 3/20
= 6, 15 + (-6 + 0.033) + 0.15
= 6, 15 - 5.967 + 0.15
= 6, 15 - 5.817
= 6, 9.183

So, 6, 15 + (-6 1/30) + 3/20 = 6, 9.183