Skill: Build rectangular arrays

An array is a group of objects arranged in equal rows and equal columns.

Example: Make an array with 12 counters.

1. Put the counters in 3 equal rows, with 4 counters in each row:

   ● ● ● ●
   ● ● ● ●
   ● ● ● ●

2. Count by rows using repeated addition:

$$4+4+4=12$$

3. Write the multiplication equation:

$$3\times4=12$$

This means 3 rows of 4 make 12.

4. You can turn the array around:

   ● ● ●
   ● ● ●
   ● ● ●
   ● ● ●

   Now there are 4 rows of 3, so:

$$3+3+3+3=12$$ $$4\times3=12$$

Both arrays have the same total, 12. Turning an array around switches the factors, but the total stays the same.