(1) direct solution: find the average value with a formula, which is a method produced by the idea of "equal division". Total quantity/total number of copies = average value

(2) Cardinal method: average by formula. Here, the smallest number is set as the radix, which is a method produced by the idea of "make-up difference". Radix+difference between each number and radix ÷ total number of copies = average.

The sum of five numbers divided by five equals the average of these five numbers.

250m times10min = 2500m.

7000m-2500m = 4500m

4500 divided by 180=25 minutes.

Total mileage of 7000m divided by total time (10+25=35) = average speed of 200m/min.

The average formula is:

(1) average = total quantity ÷ total number of copies.

Total quantity = average x total number of copies

Total number of copies = total quantity/average value

② Average value = benchmark number+sum of differences between each number and benchmark number ÷ total number of copies.

When the sum of n numbers is divided by n, the quotient is called the arithmetic average of these n numbers.

Average algorithm:

There are two common methods to calculate the average: one is the simple average method, and the other is the weighted average method. For example, an enterprise produces a set of product 10, and the unit price is 100 yuan; 5 sets of B products are produced in 50 yuan at the unit price; Three sets of C products were produced at the unit price in 30 yuan, and the average price was calculated. Simple average method: average price = ∑ unit price/product category of various products.