Arrays and estimating

In an array, rows go across and columns go up and down. This array has 3 rows and 4 columns, so we call it a 3 by 4 array. Count the objects in one row and add the rows: 4 + 4 + 4 = 12. Count the objects in one column and add the columns: 3 + 3 + 3 + 3 = 12. The total is 12 both ways. The number of rows tells how many numbers you add when you add the rows. The number of columns tells how many numbers you add when you add the columns.