Multiple Towers-Understanding Multiples and Patterns
"The tenth multiple has a zero at the end!" exclaimed one student.
"Of course," responded another. "All multiples of tens end in zero."
"Oh yeah," agreed the first student.
"Will that help you find the 20th multiple?" I asked the students. "The 10th number or the 20th number multiples are called landmark numbers. We will use these to help us with our study of multiplication.
This is a conversation we had in the fourth grade while making multiple towers as a part of our study of large digit multiplication. Using Post Its, markers and a two-digit multiple the students counted up to at least the 20th multiple. Then they looked for patterns and landmark numbers. Landmark numbers are numbers that make math simpler by virtue of it being easy to relate to and calculate with. They are familiar landing places.
The idea of finding familiar landing places, especially using the "10s," is a concept that shows up throughout the Investigations curriculum as a strategy for simplifying larger digit calculations. In this unit students use it in this way for example:
27 X 15=
Students break up the 15 into 10 and 5. Then they calculate 27 X 10 and 27 X 5 and add the answers for the solution.
The students will continue to use the strategy of landmark numbers and multiple towers as we move from multiplication into our study of division.
"Of course," responded another. "All multiples of tens end in zero."
"Oh yeah," agreed the first student.
"Will that help you find the 20th multiple?" I asked the students. "The 10th number or the 20th number multiples are called landmark numbers. We will use these to help us with our study of multiplication.
This is a conversation we had in the fourth grade while making multiple towers as a part of our study of large digit multiplication. Using Post Its, markers and a two-digit multiple the students counted up to at least the 20th multiple. Then they looked for patterns and landmark numbers. Landmark numbers are numbers that make math simpler by virtue of it being easy to relate to and calculate with. They are familiar landing places.
The idea of finding familiar landing places, especially using the "10s," is a concept that shows up throughout the Investigations curriculum as a strategy for simplifying larger digit calculations. In this unit students use it in this way for example:
27 X 15=
Students break up the 15 into 10 and 5. Then they calculate 27 X 10 and 27 X 5 and add the answers for the solution.
The students will continue to use the strategy of landmark numbers and multiple towers as we move from multiplication into our study of division.
This group of boys wanted their tower to reach the ceiling.
This partnership found three landmark numbers in their tower.
