Unsquaring Numbers

Everyday Math Lesson 1.8

Lesson Objectives

• I can tell the difference between powers of ten written as ten raised to an exponent.

• I can show powers of 10 using whole number exponents

Vocabulary• Add the following vocabulary

word to your vocabulary chart:

–Square Root

Mental Math5 x 6 9 x 5 7 * 93 x 9 7 * 8 8 * 77 x 7 6 * 7 9 * 76 x 6 9 x 6 8 * 9

8 x 66 x 97 * 66 * 8

Math Message• Find the numbers that make these

statements true. If you need counters, you may use them to help you.

___x ___ = 4

___² = 81

“Unsquaring” Numbers• What is the difference in squaring and unsquaring a

number?– When you multiply a number by itself, you square the

number. • 4 x 4 = p – Square the number 4 to find P• P = 16

– When you “unsquare” a number, you must undo the operation in order to find the number that was squared.• N * N = 16• N = 4

Let’s try some more!• In your work journal “unsquare” the following

numbers:– 196– 10,000– 900– 3, 136

Your Turn• With your assigned partner, complete

problems 1 and 2 on Student Journal Page 23.

• You will have 15 minutes to work, when time is called be ready to share your answers.

Finding the Square Root• How can we check our answers to problem

one?–Multiply the square root of a number by

itself. The symbol for square root is √– You can use the square root key on your

calculator to help you find these answers.• EX: 8² = 8 x 8 = 64 The square root of 8 is

64 and the square root of 64 is 8.

Using the √ key on your calculator

• Check your answers to problem 2 by completing the following:– Enter the number for which you are trying to find

the square root.– Press the √ key, and then press = or enter.– If the answer is a whole number, then the number

you entered is sqaure.– If the answer is a decimal number, the number

you entered is NOT square.

Your Turn!• With your assigned partner, complete Student

Journal Page 23 problems 3-6.

• You may also finish checking the answers to problem 2 with your calculators.

• You will have 15 minutes to work, when time is called be ready to share your answers.

Writing/Reasoning

• Get out your Work Journal.

• Write a response to the following: Was Jason correct when he said that 64 is a prime number in Problem 3? Explain your answer. Use vocabulary words when appropriate.

Let’s Play Multiplication Top-It

• Read the directions for playing this game on SRB page 333 and 334.

• You will use a record sheet to keep track of the game. This will be your exit slip for today’s class.