The mean or average of the numbers -410 and 400 is -5. It is found by adding the two numbers together and dividing the sum by two.
They are all the numbers that end with 0
410
410
The count of the numbers is 410+1+400 = 811. To get the sum of all these numbers note that all the positive numbers cancel with their negative counterparts and you are left only with the numbers from -410 to -401 (inclusive). The sum of these numbers is -4055. So their mean is Sum/Count = -4055/811 = -5.
410
390, 400
Average of five numbers is 82 so their sum is 82*5 = 410. Average of four of them is 80, so their sum is 80*4 = 320. So the fifth number is 410 - 320 = 90.
380 and 410
The average of 330 and 410 is 370.
410 rounded to the nearest hundred is 400
400