Calculate $20\times18$20×18 by completing an area model.
Firstly, complete the missing values in the area model.
| $\times$× | $20$20 |
|---|---|
| $10$10 | $\editable{}$ |
| $8$8 | $\editable{}$ |
Now add the values you found in part a to calculate $20\times18$20×18.
Let's use the area model to find $27\times12$27×12.
Use the area model to find $44\times33$44×33.
Use the area model to find $77\times66$77×66.