What is the value of 3 in the number 42.7531?

Analyze the question: We need the place value of the digit 3 in 42.7531.

Concept: After the decimal point, each digit's place value decreases by a factor of 10:

• 1st place: tenths (1/10)
• 2nd place: hundredths (1/100)
• 3rd place: thousandths (1/1000)
• 4th place: ten-thousandths (1/10000)

Solution:

Number: 42.7531

| Digit | Place | |-------|-------| | 7 | tenths | | 5 | hundredths | | 3 | thousandths | | 1 | ten-thousandths |

The digit 3 is in the third decimal place, which is the thousandths place.

Value of 3 = 3 × (1/1000) = 3/1000

Answer: Option B, 3/1000.

Tip: Count the decimal places from the point: the 1st is tenths, the 2nd is hundredths, the 3rd is thousandths, and so on. The number of zeros in the denominator equals the position, so the 3rd decimal place gives 1000 (three zeros). Don't confuse "place value" with "digit value": the place value includes the position (3/1000), while the digit value is just 3.