Question

what is the nearest ten and hundred of 829 when it is round

Answer 1

$829 \to 830\ (ten)\\\\829 \to 800 \ (hundred)$

Answer 2

If you are rounding to the nearest tens place then the answer is 830(29 is closer to 30 than 20. If you are rounding to the nearest hundreds place then its 800(829 is closer to 800 than 900).