Final answer:
To express 4/10 as a decimal number, divide the numerator (4) by the denominator (10) to get 0.4. Another decimal number equal to 4/10 is 0.40.
Step-by-step explanation:
To express 4/10 as a decimal number, we divide the numerator (4) by the denominator (10). This gives us 0.4. Therefore, 4/10 expressed as a decimal number is 0.4. Another decimal number equal to 4/10 is 0.40, which is the same value represented with an additional zero after the decimal point.