Question

How many significant figures does each value contain?

The measurement 400 mL has significant figures.
The measurement 208 ft has significant figures.

Answer 1

400 mL has 1 significant digit.

208 has 3 significant digits.

Answer 2

The measurement 400 mL has one significant figure.

The measurement 208 ft has three significant figures.

Explanation:

Non-zero digits are always significant.

Zeros between significant digits are also significant.

Trailing zeros are significant only after a decimal point.

400 has only one significant figure. 4 is a non-zero digit, so it's significant. Trailing zeros in a whole number aren't significant.

208 has three significant figures. 2 and 8 are non-zero digits, so they're significant. The 0 is between significant figures, so it's also significant.