The number 84 rounded to the nearest 10 is going to be 80.
It ends in 4, so it rounds down to 80.
80
80
100
80
It's nearer 84 than 83, so 84 is the answer.
45 + 39 = 84, so if you want to round to the nearest ten, that's 80, or nearest hundred is 100. Otherwise, it doesn't turn out to a decimal, so it doesn't need rounding to the nearest one.
The cube root to the nearest ten thousandth is 4.3795...
It depends on the level to which you wish to round. To the nearest unit: 84 To the nearest thousand: 0
880
84 rounds up to 100. 22 rounds down to zero.
84