Solving Multiplication and Division Equations

Multiply & Divide Equations 1) GOAL: Get the variable on one side of the equation. 2) You always perform the same operation to both sides of an equation. 3) To undo an operation you perform its opposite operation to both sides of the equation.

Multiply & Divide Equations The inverse of add is SUBTRACT The inverse of subtract is ADD The inverse of multiply is DIVIDE The inverse of divide is MULTIPLY

Multiply & Divide Equations What you do to one side of an equation, you must do to the other side to keep it balanced. = 30 5 x 6

To solve a multiplication equation Multiply & Divide Equations To solve a multiplication equation Use the inverse operation for multiplication which is division. Get the variable alone, by dividing the same number into both sides.

Try to solve this multiplication equation. Multiply & Divide Equations Try to solve this multiplication equation. How do you get x all by itself? = 8x 56

Multiply & Divide Equations Divide 8 into both sides. = 8x 56 7 8 8

•7 = 8x 56 Divide 8 into both sides. Multiply & Divide Equations Divide 8 into both sides. Check your answer by substitution! = 8x •7 56

Try to solve this multiplication equation Multiply & Divide Equations Try to solve this multiplication equation How do you get x all by itself? = 42 7x

Multiply & Divide Equations Divide 7 into both sides. = 42 7x 6 7 7

•6 Divide 7 into both sides. = 42 7x Multiply & Divide Equations Divide 7 into both sides. Check your answer by substitution! = 42 7x •6

To Solve a Multiplication Equation Multiply & Divide Equations Divide the same number into both sides To Solve a Multiplication Equation 8x = 32 Get the variable alone. 8 8 Divide 8 into both sides. x = 4 8 divided by 8 cancels out 8 • 4 = 32 Show your check! 32 = 32 Finish your check!

Multiply & Divide Equations 1) 3) 2) 4)

To solve a division equation Multiply & Divide Equations To solve a division equation Use the inverse operation for division which is multiplication. Get the variable alone, by multiplying the same number to both sides.

Try to solve this division equation Multiply & Divide Equations Try to solve this division equation How do you get x all by itself? x 3 = 15

Multiply & Divide Equations Multiply both sides by 3 x 3 = •3 45 •3 15

45 x = 3 15 Multiply both sides by 3 Multiply & Divide Equations Multiply both sides by 3 Check your answer by substitution! 45 x 3 = 15

Try to solve this division equation Multiply & Divide Equations Try to solve this division equation How do you get x all by itself? x 6 = 4

Multiply & Divide Equations Multiply both sides by 6 x 6 = •6 24 4 •6

24 x = 6 4 Multiply both sides by 6 Check your answer by substitution! Multiply & Divide Equations Multiply both sides by 6 Check your answer by substitution! 24 x 6 = 4

Try to solve this division equation Multiply & Divide Equations Try to solve this division equation How do you get x all by itself? x 7 = -7

Multiply & Divide Equations Multiply both sides by 7 x 7 = •7 -49 -7 •7

-49 x = 7 -7 Multiply both sides by 7 Multiply & Divide Equations Multiply both sides by 7 Check your answer by substitution! -49 x 7 = -7

To Solve a Division Equation Multiply & Divide Equations To Solve a Division Equation Multiply the same number to both sides. x 3 = 25 Get the variable alone. 3• •3 = 25 x 3 Multiply both sides by 3. 3 divided by 3 cancels out to 1. x = 75 Show your check! Finish your check! 25 = 25

Try These Equations Show your check! Multiply & Divide Equations Try These Equations Show your check! -3x = 21 m = 8 -2 (-2) -3 -3 m = -16 x = -7 -3(-7) = 21 21 = 21 8 = 8

Multiply & Divide Equations Try These Equations 1) 2)

Multiply & Divide Equations Try These Equations 3) 4)

Take Out Your Study Guide!!! Multiply & Divide Equations That's all Folks! That’s all folks Take Out Your Study Guide!!!

To Solve a Multiplication Equation #5 To Solve a Multiplication Equation Divide the same number into both sides 5x = 40 Get the variable alone. 5 5 Divide 5 into both sides. x = 8 5 divided by 5 cancels out to 1. 5 • 8 = 40 Show your check! 40 = 40 Finish your check!

To Solve a Division Equation #6 To Solve a Division Equation Multiply the same number to both sides x 2 = 20 Get the variable alone. = 20 2• •2 x 2 Multiply both sides by 2. 2 divided by 2 cancels out to 1. x = 40 Show your check! Finish your check! 20 = 20

Teacher Note: The following slides may be inserted at the beginning of the lesson if the lesson is also teaching writing expressions and/or equations.

Multiply & Divide Equations Add Subtract Multiply Divide plus minus times quotient difference sum product of increased by decreased by less twice total more than less than subtracted from added to Flip Flop Numbers

Multiply & Divide Equations Placement Rule Always write the variable after the number! a 4 WRITE IT AS 4a

Parentheses mean multiply! Multiply & Divide Equations Using Parentheses 8 x is written as 8(x) (8)x (8x) 8x Parentheses mean multiply!

Multiply & Divide Equations Translate the following into equations. 1) Eleven more than a number t is 23. 2) Eight times a number k is equal to 56. 3) Thirteen less m equals 6. 4) The quotient of x and 3 is 18.

Multiply & Divide Equations Write a phrase that describes each variable expression below. Four times the sum of m and 5 minus 3 Five minus twice the quotient of x and 8 The quotient of a and 7 minus 3

Teacher Note: The following slides may be inserted at the end of the lesson if the lesson is also teaching solving equations with fractions.

Multiply & Divide Equations Short Way Long Way Easier to multiply by the reciprocal!

Solve the division by multiplying by the reciprocal. Multiply & Divide Equations Solve the division by multiplying by the reciprocal.

Solve the division by multiplying by the reciprocal. Multiply & Divide Equations Solve the division by multiplying by the reciprocal.

Solve the division by multiplying by the reciprocal. Multiply & Divide Equations Solve the division by multiplying by the reciprocal.

To Solve a Fraction Equation #7 Multiply both sides by the reciprocal of the fraction. Multiply the numerators. Multiply the denominators. Simplify

If you have trouble viewing you need MathType software: To see all math formulas correctly you need to install MathType software, similar to equation editor and is available for free at Design Science website .

For more information on Math Slideshows visit: http://www