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 5x6 3x9 7x7 6x6 9x5 7*8 6*7 9x6 8x6 6x9 7*6 6*8 7*9 8*7 9*7 8*9 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.