Which of these are correct?
0.1+0.1=0.20.1 + 0.1 = 0.20.1+0.1=0.2
15+15=0.4\frac{1}{5} + \frac{1}{5} = 0.451+51=0.4
0.5+0.5=10.5 + 0.5 = 10.5+0.5=1
14+14=0.25\frac{1}{4} + \frac{1}{4} = 0.2541+41=0.25