Final answer:
The highest common factor (HCF) of the numbers 325, 390, and 455 is determined by long division. By dividing the smallest number by prime numbers, and checking if the result divides the other numbers, we find that the HCF is 65.
Step-by-step explanation:
To find the highest common factor (HCF) of the numbers 325, 390, and 455 by long division, we identify the largest number that divides into each of the numbers without leaving a remainder.
Start by dividing the smallest number (in this case, 325) by a prime number (such as 5).
Check if the result (65) also divides the other two numbers.
If it does, as in this case (390 ÷ 65 = 6, 455 ÷ 65 = 7), that number is the HCF.
Therefore, the HCF of 325, 390, and 455 is 65.
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