How many significant figures are in each number?
a. 0.000312 m
b. 312,000 s
c. 3.12 X 105 km
d. 13,127 s
So in this question guys what we're asked is to determine the number of significant figures from each one of the values given to us so in the first one here we have a decimal point, remember when you have a decimal point we're going to move from left to right, we start counting once we get to our first non-zero number so skip skip skip skip 3 is our first non-zero number once we start counting we have to count all the way until the end so this has 1 2 3 sig figs, for the next one it has no decimal points so we go the opposite direction we're going right to left now here though the first number that we pass is a 0 when there is no decimal point and we're going from right to left if the first number we pass is a 0 that means that we have an infinite number of significant figures. For the next one we have a decimal so again we go are left to right our first non-zero number is this 3 so we count all the way through 1 2 3 sig figs, no decimal point we go from right to left, first non-zero number is the 7 so we count all the way through 1 2 3 4 5 sig figs and then here the last one no decimal point so we're going to go from right to left, first number we pass that was a 0 so this has an infinite number of significant figures. So just remember the fundamental rules of if we have a decimal point or not determine which direction we move in.