Question

use the model to find 51 × 49. first, find the area of each rectangle. then, find the total area. 51 × 49 =

Explanation:

Step1: Calculate area of top - left rectangle

The dimensions of the top - left rectangle are 50 and 40. The area of a rectangle is length times width, so the area $A_1=50\times40 = 2000$.

Step2: Calculate area of top - right rectangle

The dimensions of the top - right rectangle are 50 and 9. So the area $A_2=50\times9=450$.

Step3: Calculate area of bottom - left rectangle

The dimensions of the bottom - left rectangle are 1 and 40. So the area $A_3=1\times40 = 40$.

Step4: Calculate area of bottom - right rectangle

The dimensions of the bottom - right rectangle are 1 and 9. So the area $A_4=1\times9=9$.

Step5: Calculate total area

The total area is the sum of the areas of the four rectangles. $A = A_1+A_2+A_3+A_4=2000 + 450+40 + 9=2499$.

Answer:

2499