What is the decimal .387123 rounded to the nearest thousand

0.387123

Note the place value of each digit

0
.
3 (tenths)
8 (hundredths)
7 (thousandths)
1 (ten thousandths)
2 (hundred thousandths)
3 (millionths)

to find the nearest thousandths, look at the place value of the ten thousandths. It is a 1. Because it is less than 5, you round down.

0.387123 becomes 0.387

0.387 is your answer

hope this helps

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"