1 significant figure.
Four
Two of them.
Two of them
3 of them.
4000000
One - the zeros are placeholders unless indicated.
There are four significant digits in the number 1.071.
Three significant digits.
This number has seven significant digits.
All four of the digits given are significant digits.
There are two significant digits in the number 83.
All numbers which are not "zero" are classed as significant digits. Therefore in the number 129 there will be three digits which are classed as significant.
There is one significant figure (which I assume you are referring to).However there are 7 digits involved, of which all are significant. Each digit is important and special in its own right. None should be singled out as being different, as that is Digitist.* * * * *Leaving aside the political correctness of the anti-digitism, the number of significant digits depends on the context. In the above example, if it is known that the number is not 3,999,999 nor 4,000,001 then all seven digits are significant. If it is known that the number is 4,000 thousand (not 3,999 thousand or 4,001 thousand) then there are 4 sig digs.
Two. All nonzero digits are significant.
There are 2 significant digits: 5 and 4
1 significant figure.