# Addition and Subtraction Expressions © 2007 M. Tallman.

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Addition and Subtraction Expressions © 2007 M. Tallman

Variable variable: a symbol (usually a letter) used to represent an unknown number. 4 = X + 3 © 2007 M. Tallman

Algebraic Expression algebraic expression: a combination of numbers and variables that represent a relationship or pattern. 4 = X + 3 © 2007 M. Tallman

Algebraic Expression You can use algebraic expressions to represent various situations. John ate 2 more pieces of cake than Mike. How many pieces did John eat? Lynn picked 12 oranges from the tree. How many oranges were left? J 2 M = + 12 o = x - © 2007 M. Tallman

Algebraic Expression Mandy purchased 3 books. Ken bought b more books than Mandy. How many books did Ken buy? Jessica had c cookies. She gave 7 cookies to Ben. How many cookies did Jessica have left? 3 b K = + c 7 J = - © 2007 M. Tallman

Algebraic Expression B
Beverly had i brownie squares. She ate ½ square. How many brownie squares does she have left ? Doug had s stamps. He was given 5 new stamps for his birthday. How many stamps does he have? i = D s 5 = + © 2007 M. Tallman

Evaluate Algebraic Expressions
Evaluate means solve. t + 33 t + 33 , t = 6.8 6.8 = t + 33 39.8 © 2007 M. Tallman

Evaluate Algebraic Expressions
Evaluate means solve. n - 15 n - 15 , n = 21 21 = n - 15 6 © 2007 M. Tallman

Evaluate Algebraic Expressions
m + 16, m = 4 p – 6, p = 8.9 7 ½ + x, x = 11 b – 3.5, b = 10 32 – y, y = 12.7 20 2.9 18 ½ 6.5 19.3 © 2007 M. Tallman

c t Rule: t = c + 5 or, c = t - 5 5 1 6 2 7 3 8 4 9 8 ? Rule ?
The adult members of an environmental club plant a total of 5 trees. Each of the 8 children in the club plant 1 tree. How many trees are planted? Rule: t = c + 5 Rule ? or, c = t - 5 c t Adults + 0 Children Adults + 1 Child 5 1 6 2 7 3 8 Adults + 2 Children Adults + 3 Children Adults + 4 Children 4 9 8 13 ? c = children t = trees © 2007 M. Tallman

Rule: t = c + 5 or, c = t - 5 13 9 4 8 3 7 2 6 1 5 t c t = trees c = children Use the function rules to answer these questions: How many trees will be planted if 11 children are in the club? If 29 trees are planted, how many students are in the club? How many tree will be planted if 20 children are in the club? If 50 trees are planted, how many children are in the club? 16 24 25 45 © 2007 M. Tallman

Rule: c = e + 1, Rule ? or e = c - 1 Element # (e) # of Cubes (c) 1 2 3 1 2 2 3 3 4 4 5 5 6 6 7 4 5 6 © 2007 M. Tallman

Rule: c = e + 1 or, e = c - 1 Use the function rules to answer these questions: How many cubes are in element 38? Which element has 37 cubes? How many cubes are in element 1,001? Which element has 78 cubes? 7 6 5 4 3 2 1 # of Cubes (c) Element # (e) 39 36 1,002 77 © 2007 M. Tallman