Question

Don’t Forget the Rules – look them up if you have to. Answer the following with "always", "sometimes", or "never":

• Non-zero digits are ________________ significant.
• Zeros between two significant digits are __________________ significant. (I like to call these "sandwich zeros")
• Leading zeros, (zeros to the left of the first non-zero digit) are ____________________ significant.
• Trailing zeros, (zeros to the right of the last non-zero digit) are ____________________ significant if they are in a number with a decimal point.

Answer 1

1. always
2. always
3. never
4. always

Explanation:

As the problem statement suggests, look up the rules if you have to.

In the case of trailing zeros, the decimal point makes them significant.

__

In a number without a decimal point, such as 300, the zeros are sometimes significant. (Different authors may tell you the zeros are never significant in such a number. The problem comes when, for example, you're trying to represent 296 rounded to the nearest 10. That is 30. tens--with 2 significant digits, just as 286 rounded to the nearest 10 would be 290--with 2 significant digits. In some numbers, you cannot tell the difference between a 0 that is a placeholder and a 0 that is present because the value of the number cannot be represented exactly any other way.)