Name _____________________________________________________________________ Date ___________________________ Using the Area Model to Multiply We can use an area model to multiply numbers. Example: 13 x 12. In order to use the area model, a good math student must remember how to write a number in expanded form. Example: 57 = 50 + 7 145 = 100 + 40 + 5 Write the following numbers in expanded form. 23 = ___________________________________ 86 = __________________________________ 37 = ___________________________________ 92 = __________________________________ 456 = __________________________________ 871 = _________________________________ Let’s try one together. Multiply 4 x 56. ü First, draw a 1 by 2 array (rectangle). ü Then use the expanded form of a number to label the array. ü Next, multiply to find the area of each smaller box in the array. ü Finally, add up all of the areas (products) to find the answer to 4 x 56. Try these. 8 x 24 3 x 72 Let’s try another together. Sometimes, the factors (the numbers I multiply together) are both 2-­‐digit numbers. Multiply 42 x 59. ü This time, draw a 2 by 2 array (rectangle). ü Then use the expanded form of a number to label the array. ü Next, multiply to find the area of each smaller box in the array. ü Finally, add up all of the areas (products) to find the answer to 42 x 59. Try this one. 23 x 74 Now you are ready to use the area model to multiply numbers. Great job. Solve the following. 2 x 93 9 x 81 16 x 34 52 x 75 67 x 47 31 x 82 The Wizard’s Challenge 34 x 762