The answer is 5.40 (can also be written as 5.4).
Below I have labelled the numbers with their place values. U is Units, th is tenths and hth is hundredths.
U th hth
5. 4 3
Rounding with decimals follows the same rules as rounding whole numbers. When rounding to the nearest tenth, you need to look at the hundredths column. If the numbers are 1-4 round down to the nearest tenth. If they are 5-9 round up to the nearest tenth.
In this case the number would become 5.40 if the number you was rounding was any of the following- 5.41, 5.42, 5.43, 5.44.
It would round to 5.50 if the number was 5.45, 5.46, 5.47, 5.48, 5.49
543 rounded to the nearest tens place is 540.
540
543
500
500
0
543,210 rounded to the hundred thousands place is 500,000
In the decimal system a tenth is 0.1 so there are no tenths involved here and the rounding is no approximation: 543.0
It is: 500
Five hundred forty.
It is: 3543 = 3500 to nearest 100
It is: 8,500