Warm Up
Finding a product mentally can be done by changing the way you look at a multiplication problem.
For example, can be thought of as . For some people, this might be easier to calculate mentally since you can imagine the solution as , or 351. This method leverages the distributive property of multiplication over addition.
For the following questions, find each product mentally. Then, explain how you changed the way you looked at each multiplication problem to use the distributive property.
Enter the product and your explanation.
Compare your answer:
99
For example, can be thought of as . This simplifies to , or 99.
Enter the product and your explanation.
Compare your answer:
399
For example, can be thought of as . This simplifies to , or 399.
Enter the product and your explanation.
Compare your answer:
9999
For example, can be thought of as . This simplifies to , or 9999.
Enter the product and your explanation.
Compare your answer:
11,009
For example, can be thought of as . This simplifies to , or 11,009.