Final answer:
The fractions 1/2 and 9/10 written with the least common denominator are 5/10 and 9/10 respectively since 10 is the smallest number that both original denominators can divide into without a remainder.
Step-by-step explanation:
To write fractions for 1/2 and 9/10 using the least common denominator (LCD), we need to find a number that both denominators (2 and 10) will divide into evenly.
The LCD for 2 and 10 is 10 since 10 is the smallest number that both can divide into without leaving a remainder. To convert 1/2 to a fraction with the LCD as the denominator, we need to find a number that we can multiply both the numerator and denominator by to make the denominator 10.
Multiplying both the numerator and denominator of 1/2 by 5 gives us 5/10. The fraction 9/10 already has the LCD of 10, so we do not need to change it.
Therefore, 1/2 can be written as 5/10, and 9/10 remains the same when using the least common denominator of 10.