Formula anomaly

1 A B C D E F
2 What is wrong with the following?
3 The totals for these two sets of figures are the same - or are they
4 If you subtract one from the other using the simplest of formulas the answer is precisely zero
5 But if you introduce brackets into the formula the answer is not quite zero. How is that possible?
6
7 enter: 0.7 0.7
8 enter: 0.7 0.7
9 enter: 0.7 0.7
10 enter: 0.0 0.7
11 enter: 1.4 0.7
12 Totals 3.5 3.5
Difference between 2 totals: 0.000000000000000000000 using formula: =B12-C12
-0.000000000000000444089 using formula: =(B12-C12)

If you alter the original figures the anomaly usually disappears.
If you enter the same figures and formulas in a new spreadsheet the same thing happens.
I have Excel 2013 but I have tried the same thing in 2007 and 2016 versions with same result
See attachment for clearer explanation