One of them.
There are four significant digits in the number 1.071.
This number has seven significant digits.
Three significant digits.
4000000
250 million = 250,000,000. There are 9 digits in this number.
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.
200,000,000 9 digits.
Two. All nonzero digits are significant.
There are 2 significant digits: 5 and 4
There are four significant digits in the number 6.741.