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9.7.14. Learning Objectives. We will evaluate 1 numerical expressions involving rational numbers.
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9.7.14 Learning Objectives • We will evaluate1 numerical expressions involving rational numbers. • Students will be able to group symbols dictating the order of applying calculations and how the absence or different placement of these symbols can lead to different results given the same numbers and operations. • Use parentheses, brackets, or braces in numerical expressions, and evaluate expressions with these symbols. What are we going to learn? What does evaluate mean? Evaluate means __________. CFU Common Core Standard 7.NS.1 & 7.NS.2 Prerequisite Skills Apply and extend previous understandings of addition, subtraction, multiplication, and division of integers (AND other rational numbers); Students will reinforce skills learned in 6th grade. 99 18 – 81 Students, you already know how to evaluate simple expressions. Now, we will evaluate numerical expressions that include grouping symbols. Make Connection Activate Prior Knowledge Evaluate from left to right. 1. 4 12 + 38 2. 10 × 6 + 8 1 find the value Vocabulary 48 + 38 60 + 8 86 68
Concept Development • A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. ( ) parentheses Grouping Symbols CFU 3 + (42 – 16) To evaluate the numerical expression above, which operation would be calculated first? How do you know? A 3+ 42 B 42 – 16 In your own words, what do grouping symbols mean in a numerical expression? “Grouping symbols mean _______.” Evaluating Numerical Expressions Without Grouping Symbols With Grouping Symbols 10 6 + 8 10 (6 + 8) 60 + 8 10 14 4 12–10 48–8 + 2 [ ] 68 140 4 2 40 + 2 8 42 What is the correct order of operations? 1. ___________ 2.____________ 3._____________ 4.____________
Skill Development/Guided Practice • A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. How did I/you know which operation to calculate first? CFU Evaluate numerical expressions. 1 Calculate the operation in the grouping symbols. (Evaluate) Continue to evaluate to get a final value. 1 2 1. (28 + 36) 4 2. 28 + (36 4) 28 + 9 64 4 37 16 64 4 28 9 + 16 37 When there are two separate grouping symbols, either one can be evaluated first. 3. (28+ 32) (48 – 18) 4. (72 9) (63 – 13) 60 × 30 8 × 50 1800 400
Skill Development/Guided Practice (continued) • A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. How did I/you know which operation to calculate first? CFU Evaluate numerical expressions. 1 Calculate the operation in the grouping symbols. (Evaluate) Continue to evaluate to get a final value. 1 2 98 11 7 3 – 10 × (3 + 5) and (10 × 3) + (10 × 5) 87 21 10 × 8 + 30 50 × (40 + 60) and ( × 40) + ( × 60) 1 2 1 2 1 2 1 2 80 80 + 20 30 × 100 50 50 80 marbles $50
Relevance • A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. Evaluating numerical expressions will help you when purchasing items. 1 Sam’s Electronics is having a special on their Blaze music players. What is the total price for 3 music players? (50 3) – 20 150 20 – 130 The total price is $130. Evaluating numerical expressions will help you do well on tests. 2 Sample Test Question: 18. Select the numerical expressions that have a value of 52 when evaluated. Choose Yes or No for A and B. A (10 + 3) 4 O Yes O No B 10 + (3 4) O Yes O No Does anyone else have another reason why it is relevant to evaluate numerical expressions? (Pair-Share) Why is it relevant to evaluate numerical expressions? You may give one of my reasons or one of your own. Which reason is more relevant to you? Why? CFU
A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. Skill Closure Evaluate numerical expressions. Calculate the operation in the grouping symbols. (Evaluate) Continue to evaluate to get a final value. 1 2 1. (27 – 13) 5 2. (34+ 15) (62 – 55) ÷ 14 × 5 49 7 Word Bank 14 5 49 7 Word Bank 7 evaluate calculate first parentheses 70 70 7 Access Common Core Place grouping symbols in the numerical expression so that 10 + 25 is calculated first. Then evaluate. How would the value of the expression change if grouping symbols were placed around 25 5 instead? The value of the expression would change because we would have to calculate 255 first. The answer would be 15. ( ) 10 + 25 5 5 35 7 Summary Closure What did you learn today about evaluating numerical expressions? (Pair-Share) Use words from the word bank.
Independent Practice • A numerical expression is made up of numbers connected by operations (+, –, , ). • The operation in the grouping symbols is calculated first. Evaluate numerical expressions. Calculate the operation in the grouping symbols. (Evaluate) Continue to evaluate to get a final value. 1 2 1. (56 + 28) 7 2. (56 7) + (28 7) 3. 9 (50 + 7) 4. (9 60) – (9 3) + - 84 7 9 × 57 8 4 540 27 12 513 12 513 84 7 56 4 + 12 60 × (12 + 10) 1 2 1 2 × 22 17 × (12 + 10) 11 17 × 22 374 11 water bottles 374 fluid ounces of water
Periodic Review 1 1. (13 + 20) × 4 2. (30 7) – (54 6) 3. (14 ½) + (24 ½) 33 × 4 132 210 – 9 201 7 + 12 19 264 540 Access Common Core 1. Decide if the value of the expression is less than, equal to, or greater than 52. Write a check mark in the correct column. 2. Decide if the value of the expression is less than, equal to, or greater than 27. Write a check mark in the correct column.
Periodic Review 2 1. (14+ 36) (77 – 17) 2. 40(58 – 23) 3. (32 ¼) + (40 ¼) 50 × 60 3000 40 × 35 1400 8 + 10 18 3000 1400 Access Common Core Place ( ) in the numerical expression to get the value. ( ) ( ) ( ) 1. 32 + 15 4 = 188 2. 56 8 – 4 = 14 3. 32 + 15 4 = 92 ( ) ( ) ( ) ( ) ( ) 4. 20 – 10 10 + 7 = 170 5. 56 8 – 4 = 3 6. 5 10 + 5 7 = 85
Periodic Review 3 1. (72 6) + (86 – 59) 3. 250 2. (200 ) + (50 ) 12 + 27 39 100 + 25 125 125 39 1200 Access Common Core 1. Fill in the blanks to create numerical expressions that have a value of 32 when evaluated. 4 2 6 10 2 4 ×( + ) = 42 ×( – ) = 32 ×( + ) = 32 ×( – ) = 42 ( × ) + ( × ) = 42 ( × ) + ( × ) = 32 Use INTEGERS. You may use the same one more than once if needed. 4 4 5 3 1 2 1 2 1 2 2. Fill in the blanks to create numerical expressions that have a value of 42 when evaluated. 7 3 3 10 4 7 Use INTEGERS. You may use the same one more than once if needed. 7 7 5 1