3
The 1 and the 2
To one significant digit, 37.19 is 4x101. Writing it as 40 makes it unclear as to whether you have 1 significant digit or 2.
Just the one and it is the digit 1
Three of them which are 1, 0 and 2
3
The 1 and the 2
To one significant digit, 37.19 is 4x101. Writing it as 40 makes it unclear as to whether you have 1 significant digit or 2.
They all have 1 as the first digit.
Just the one and it is the digit 1
Three of them which are 1, 0 and 2
Well, in science you always need significant digits: 0 has no significant digits, so we round to the nearest number with 1 significant digit: namely, -1 or 1.
There is one significant figure in 0.00001, which is the non-zero digit 1.
4 All of them are significant. Only zeros are potentially insignificant. And that's only when your numbers either start with zeros like 0.001 (1 significant digit 1) or end with zeros 13.0000 (2 significant digit, 13). Any zeros between non-zero numbers are significant.
When rounding 5.05 to two significant figures, we first identify the two most significant digits, which are the 5 and the 0. The digit following the last significant digit is 5, which is equal to or greater than 5, so we round the last significant digit up by 1. Therefore, 5.05 rounded to two significant figures is 5.1.
849 to 1 significant figure is 800. This is because the first non-zero digit is 8, so the significant figure is the hundreds place.
0.000892 to 1 significant figure is 0.0009 (1st significant figure is the first non-digit from the left, where in this case you can omit the number 2 since it will make no difference to the answer)