Five. Zeros that are after the decimal and are after nonzero integers are always significant.
4
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.
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.
Three significant digits.
50.4 has 3 significant digits.
There are 3 significant digits in 20.0
It has 6 significant digits.