1) If you round 14.567 to the tenths place, the answer is 14.6, ie., don't put in the trailing zeros because they would give a false sense of accuracy.
2) 35/100 is 0.35 and so is 3/10 + 50/1000. The latter boils down to 0.3 + 0.05.
3) Correct. The 4 in 476907 has the 100000 unit, and the 4 in 253491 has the unit 100. The factor to get from 100 to 100000 is 1000.
4.1) 21532.41. Every digit is presented with its unit, so you could also rewrite this as a big addition:
20000
1000
500
30
2
0.4
0.01
------------- +
21532.41
4.2) Divide by ten = move the decimal point to the left. Answer a.
5) Numbers that are smaller than 4.5 can be found by just looking at the numbers up to and including first tenth. If that is smaller than 4.5, they go in the left box. So 4.4999999999 is smaller, despite all the 9's.
Same for bigger than 4.5. The additional digits can't make it smaller...
4.8, 4.75, 4.6 and 4.89 are bigger, the rest is smaller.