990 has three significant figures.
900 of them.
Five. All nonzero digits are significant and zeros in between significant digits are significant.
This number has seven significant digits.
Three significant digits.
There are five significant digits.
2 significant figures.
4
900 of them.
It has 3 significant digits.
3 significant digits.
It has two significant digits.
Five. All nonzero digits are significant and zeros in between significant digits are significant.
890
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Five. All nonzero digits are significant and zeros in between significant digits are always significant.
Any number whose digits add up to a multiple of 3 is divisible by 3. Since the digits of 990 add up to 18, this is a multiple of 3.The sum itself: 990 / 3 = 330