79
72 73 79 75 76 81 81 85 88
They are: 79+2 = 81
81 is not prime it's a composite number
median is 79. Write in order; median is middle number: {72, 89, 67, 81, 75, 79, 81, 80, 62, 64, 83} → {62, 64, 67, 72, 75, 79, 80, 81, 81, 83, 89} To find middle number, count the number of data items, add 1 and divide by 2. If this is a whole number, that is the data item which is the median; if it is a fraction, take the mean average of the data items of the positions either side of the fraction (eg if the fraction is 3.5, take the mean average of the 3rd and 4th data items) There are 11 data items → median is (11+1)/2 = 6th data item → median is 79
83
81 is not a prime number. 81 = 3 * 3 * 3 * 3
79 and 2 if you add them.
83
To find the factors of a number, you need to try dividing it by each prime number in turn. You can stop at what would be the numbers square root. In this case the number is less than 81 so we can stop at 9. Try dividing 79 by 2, 3, 5 and 7 and you will find that none of them divide evenly. Thus, 79 is prime, and the only factors it will have are 1 and 79.
61 67 71 73 79.
No.
There is no mode because no number appears more than once.