Which number is equal to the decimal expansion (4.000)?

Correct answer: (4)

The number equal to 4.000 is 4, so B is correct. Decimal notation allows zeros to be written to the right of the last nonzero digit without changing the value: 4.000=4.000−0.000=4. The digit 4 is in the units place, while the decimal zeros represent zero tenths, hundredths, and thousandths. A, 0.4, means four tenths and is ten times smaller. C, 40, is ten times larger and has a different units value. D, 0.004, means four thousandths, also much smaller. Do not confuse trailing zeros after a decimal with a change in place value; zeros after the last nonzero decimal digit are harmless. Memory cue: 7.0, 7.00 and 7 have the same value.