There are 8 rows and 8 columns, or 64 squares on a chessboard. suppose you place 1 penny on row 1 column a, 2 pennies on row 1 column b, 4 pennies on row 1 column c, and so on … estimate: how many pennies in row 1? pennies estimate: how many pennies in rows 1-4? pennies estimate: how many pennies on the entire chessboard? pennies

This is a geometric progression with a common ratio of 2.

The sum of all the pennies in the first row (8 elements) is 
     

There are 255 pennies in row 1. 

In rows 1-4, there are 32 squares. So the sum is 
     

There are 4,294,967,295 pennies in the first 4 rows.

There are 64 squares in all. So, the sum of all pennies is 
     

There are 18,446,744,073,709,551,615 pennies on the entire chessboard. 

Idon’t know actually i’m in 5th grade and don’t know