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Home > CC2 > Chapter 3 > Lesson 3.2.4 > Problem 3-74


Mentally calculate the following products. Use the rule for decimal multiplication to write an equation in which the decimal point is written in the correct location.  

Compute without a calculator


    Think: A small number times a small number is a ____ number.

    A negative number times a negative number is a _____ number.

    Multiply and move the decimal three places to the left.



    See part (a).

  1. Stacey said, “Stephanie, look at my answer to the last problem, . Usually when I multiply, I get a bigger answer than the numbers I start with. Twenty-eight hundredths, , is less than either or . I must have made a mistake.”

    Stephanie responded, “Well, one half times one half is one fourth, and one fourth is less then one half. I think when you multiply by a fraction or decimal less than one, you get less than you started with.”

    Write a sentence or two about who you think is correct and why.

    Stephanie is correct. Why?