standard_description: Recognize that sequences are functions, sometimes defined recursively, whose domain is a subset of the integers. For example, the Fibonacci sequence is defined recursively by f(0) = f(1) = 1, f(n+1) = f(n) + f(n-1) for n ³ 1.
problem_activity: Problem 1
a.   Solve.
6 × 3 = _____
60 × 3 = _____
60 × 30 = _____
b.   What do you notice about Part (a)? What do you wonder?
Problem 2
a.   Kristen and Rajiv are finding the product 80 × 50. Kristen says to find 8 × 50, then multiply by 10. Rajiv says to find 80 × 5, then multiply by 10.
Will both Kristen and Rajiv’s methods give the correct product? Why?
Write expressions to represent Kristen and Rajiv’s methods.
b.   Find the product 80 × 50.
Problem 3
Estimate the following products.
a.   41 × 32
b.   57 × 45
c.   24 × 77


aligns: no