Two.
4
It has two significant digits.
It has 3 significant digits.
3 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.
The first 3 significant digits of a number are the first 3 digits starting from the left ignoring any leading zeros. So 31456 = 31500 (3 significant digits) The 5 in the "56" rounds the 4 up.
50.4 has 3 significant digits.
There are 4 significant digits in 5600.
This number has seven significant digits.