Figuring out the average of something is simple. It means that you take every single number in the list. Write them down or put them in a spreadsheet. That means that you add them all up for a grand total. Let’s say you have 5 ages: 31, 30, 26, 21, 10. The total or sum of those numbers is 118. That’s the average.  Using the above example, you would divide 118 (the sum of all the ages) by 5 (the number of ages in the list). The average age is 23.6. This works for much larger number sets too. For example, let’s say you wanted to find the average age of people in a club. Let’s say there were 100 members in the club. You would need the exact ages of each club member. You would add those ages together to get a sum. Then, you would divide that sum by the number 100. That’s the average age of members in the club. It’s no different when calculating average for other types of numbers that aren't ages. Average works the same way.  For example, let’s say you want to know the average population of the 10 largest cities in America. You would list the population for each city. Then, you would add all of those numbers up. You would divide the sum by 10, and that’s the average. There are times you might want to use a weighted average. For example, when averaging a student’s grades, you might want to weigh some assignments as being worth more than others.To do this, multiply each grade by the weight. Then add those numbers together, and divide by the total number of grades

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Write a summary of the previous text in Indonesian:
Tulis semua usia dalam daftar. Hitung jumlah semua angka dalam daftar. Bagi jumlah total yang tadi didapatkan dengan banyaknya data. Cari rata-rata kumpulan angka lainnya.