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 Math 5 x 6 9 x 5 7 * 9 3 x 9 7 * 8 8 * 7 7 x 7 6 * 7 9 * 7 6 x 6 9 x 6 8 * 9 8 x 6 6 x 9 7 * 6 6 * 8

Math Message ___x ___ = 4 ___² = 81 Find the numbers that make these statements true. If you need counters, you may use them to help you. ___x ___ = 4 ___² = 81 Go over the answers to these problems as a class. Give other examples of squaring and unsquaring numbers to make sure students understand.

“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 Give more examples of squaring and unsquaring to assure student understanding.

Let’s try some more! In your work journal “unsquare” the following numbers: 196 10,000 900 3, 136 Give students about 5-10 minutes to work on these examples and go over them as a class.

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. Go over the answers as a class, let students check their 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. Allow students to write the definition for square root on their vocabulary chart. Show students the square root key on their calculators to eliminate confusion.

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. Check answers as a class, let students check their work.

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. This may also be used as a formative assessment, it will also get the students in a habit of using complete sentences and vocabulary words when answering open response questions as well.

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. Students will have 15 minutes to play the game, I will collect record sheets as an exit slip/formative assessment. Students may use the remaining time to do Math Boxes and Study Link.