IM: 6.5.5: Decimal Points in Products (Lesson)

By Newsela Staff

Last updated 2 months ago

5.1: Multiplying by 10

In which equation is the value of x the largest?

How many times the size of 0.81 is 810?

5.2: Fractionally Speaking: Powers of Ten

Work with a partner. One person solves the problems labeled “Partner A” and the other person solves those labeled “Partner B.” Then compare your results.

Find each product or quotient. Be prepared to explain your reasoning.

Partner A
a.  250 \cdot 1/10  _______ 
b.  250 \cdot 1/100  _______ 
c.  48 \div 10  _______  
d.  48 \div 100  _______  

Partner B
a.  250 \div 10  _______ 
b.  250 \div 100  _______ 
c.  48 \cdot 1/10  _______ 
d.  48 \cdot 1/100  _______ 

Use your work in the previous problems to find 720 \cdot (0.1) and 720 \cdot (0.01). Explain your reasoning.

Pause here for a class discussion.

Find each product. Show your reasoning.
a.  36 \cdot (0.1)  _______ 
b.  (24.5) \cdot (0.1)  _______ 
c.  (1.8) \cdot (0.1)  _______ 
d.  54 \cdot (0.01)  _______ 
e.  (9.2) \cdot (0.01)  _______ 

Jada says: “If you multiply a number by 0.001, the decimal point of the number moves three places to the left.” Do you agree with her? Explain your reasoning.

5.3: Fractionally Speaking: Multiples of Powers of Ten

Select all expressions that are equivalent to (0.6) \cdot (0.5). Be prepared to explain your reasoning.

Find the value of (0.6) \cdot (0.5). Show your reasoning.

Are you ready for more?

Ancient Romans used the letter I for 1, V for 5, X for 10, L for 50, C for 100, D for 500, and M for 1,000. Write a problem involving merchants at an agora, an open-air market, that uses multiplication of numbers written with Roman numerals.