It is the leading digit.
It is the first or leftmost digit: 4.
When rounding 5555 to 2 significant figures, we start counting from the leftmost non-zero digit. In this case, the leftmost non-zero digit is 5. The next digit after 5 is 5, which is greater than or equal to 5, so we round up the leftmost non-zero digit. Therefore, 5555 rounded to 2 significant figures is 5600.
0.2.
It is 5000000.
It is the leading digit.
It is the first or leftmost digit: 4.
Five. Count from the first nonzero digit to the last nonzero digit.
The most significant digit.
To round off 128,674 to leave one nonzero digit, you would round it to 100,000.
There is no digit in the thousands place. There is an 8 in the thousandths place.
0.2.
It is 400.
4 Every digit between the leftmost non-zero digit and EITHER the right most non-zero digit OR the rightmost digit after a decimal.
It is 300000.
It is 6000000.
It is 300.