options: Find all factor pairs for a whole number in the range 1–100. Recognize that a whole number is a multiple of each of its factors. Determine whether a given whole number in the range 1–100 is a multiple of a given one-digit number. Determine whether a given whole number in the range 1–100 is prime or composite.
problem_activity: Task
The table below shows all the products of pairs of numbers between 1 and 9.
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Which numbers appear only once in the table of products?   Where are these numbers located in the table?  Why?
Which numbers appear the most frequently in the table?  Why?
Which numbers between 10 and 20 do  not  appear in the table?  What do these numbers have in common?


correct_option_index: 0