Algebra… Expressions and Variables 4.OA.2 and 4.OA.3

We will be learning how to find a variable in an expression and solve the expression!

First...let’s talk about what an expresson is...get your organizer! expression

Next...let’s talk about what a variable is...turn your organizer over! variable

Now that we know those two words, let’s move on to some “phrases” used to go with expressions and variables: -three more than a number -the sum of ten and a number y -nine times a number - a number decreased by three

We can easily turn these phrases into expressions with a missing number (variable). Remember when we did the multiplicative comparisons? Sixteen is two times more than eight... 16=2x8

Well, we can use the same strategy! Let’s try... -a number increased by seven looks like: n + 7 -nine times a number looks like: 9 x c -twice the number three looks like: 2 x 3 two less than three times a number: 3 x k - 2

It’s easy if you read the words carefully and make notes above the words! 8 x f Eight times a number 7 + n seven more than a number

Remember…you can use any letter of the alphabet to represent a missing number. It’s best not to use x, though…why?

Let’s review some words to show the four operations: Subtraction minus difference less than fewer than decreased by

Addition plus added to greater than more than increased by total the sum of in all

Multiplication times product at double twice triple of multiplied by

Division divided equally quotient of half of goes into per each

Now, let’s try this out! Mrs. Harbour will pass out a graphic organizer/practice sheet, so beeeeeeeee ready to dive in!

OK…let’s look at this practice organizer. Remember to make notes above the phrases. -the quotient of a number and thirty-one -the product of a number and four - seventy-one more than a number

-the difference between sixty-three and a number -the sum of thirty-five and a number -the quotient of nineteen and a number -a number decreased by twenty-one -the quotient of five and a number

-a number increased by fifty-two -twenty-six more than a number -eighty-three less than a number -fifty-six less than a number -the product of eighty and a number -a number decreased by eighty

You did it!!!