0.3 rounded to 1 dp IS 0.3!
To 4 DP, 62.1935 To 3 DP, 62.194 To 2 DP, 62.19 To 1 DP, 62.2
It is 2.2 rounded to one decimal place
It can't be rounded any further, so it is 570.
.9 is already rounded to 1 decimal place. To 2 dp it is 0.90
7.5
0.3 rounded to 1 dp IS 0.3!
To 4 DP, 62.1935 To 3 DP, 62.194 To 2 DP, 62.19 To 1 DP, 62.2
570
It is 2.2 rounded to one decimal place
0.17
To 1 dp, 0.46 → 0.5
6.4 4.28 + 2.15 = 6.43 = 6.4 rounded to 1 dp.
7.874 DP (rounded)
It is rounded to 15.3913
1.555... or 1.56 rounded (to 2 dp).
You relax and do nothing. The number is already rounded to 1 dp.