Significant Numbers?

Question

"Zeros at the end of a number are significant only if they are indicated to be so through the use of scientific notation."

I don't understand this concept. Can someone help me please?

Answer 1

This statement simply describes how people normally write numbers. If I tell you the boat weighs 5000 pounds, and it actually weights 5315 or 4822, I am still correct. By customary usage, this number has only one significant figure of precision.

But see the reference on neutron, where the mass of the neutron is cited as 1.674 927 29(28) × 10−27 kg. The number in parentheses says the last two digits of the numeric value can vary by 28 in either direction, and the answer will be within one standard deviation in the distribution of all possible answers. This number has 7 or 8 significant figures of precision. The same would be true if the value were 1.600 000 00(28) x 10-27 kg.

Answer 2

100 is 1sig #
100. is 3 sig fig , note theres is a dot

depends on the accuracy of something
eg. the first one maybe range from 100 to 149
but the second one range from 100.0 to 100.5
as you can see the difference is great

1.0 x 10^y has 2 actually
1.000 x 10^y has 4
the guy above is wrong

Answer 3

the number 3000000 only has 1 significant digit unless otherwise noted

3.0x10^ has one
3.000x10^6 has three