Writing and Evaluating Expressions with Addition and Subtraction 03:14 minutes

Video Transcript

Transcript Writing and Evaluating Expressions with Addition and Subtraction

Spooky! Is this a horror movie? No, it’s just Halloween in the 'burbs! It seems like the neighborhood kids really scored at trick-or-treating. But although their bags are full of treats, not every treat is their favorite. So the kids want to exchange with each other. The witch is jubilant for jelly beans, the scarecrow salivates for sour sweets and the pumpkin is partial to peppermint. To exchange for the treats they really want, these kids need to know how to write and evaluate expressions using addition and subtraction. Before the trick-or-treaters can exchange their goodies they have to figure out who has what candy. How many bags of sour sweets does the scarecrow have?

Preparation - addition in expressions

Let’s get organized by writing the information we know. The scarecrow has 6 more bags of sour sweets than the pumpkin and the pumpkin has 5 bags of sour sweets. So, to calculate out how many bags of sour sweets the scarecrow has, we turn these words into a mathematical expression. The keyword “more” helps us know that we should add 6 to the number of treats the pumpkin has. We know the pumpkin has 5 sour sweets, so we can replace the words with 5. This gives us 6 plus 5, which equals 11 sour sweets. This means that the Scarecrow has 11 of his favorite sweets in total. We still have more candy left. The witch has 3 packs of jelly beans. The pumpkin has 6 more packs than the witch does. Then, the pumpkin receives 7 packs of jelly beans from the scarecrow. Now, how many more packs will the pumpkin have than the witch? Let's work the problem step-by-step to translate words to numbers and operations. As we know, the witch has 3 packs of jelly beans. And earlier we said that the pumpkin has 6 more. Saying 'more' means we should use the addition operation to get the number of packs of jelly beans the pumpkin has. Since we already know the witch has 3 packs of jelly beans, we can just substitute that in our expression and evaluate. Since the pumpkin receives 7 packs of jelly beans from the scarecrow, we can add that to our earlier sum and get 16.

Solution - subtraction in expressions

Have we solved the question? Not yet. Since the question asked how many more jelly beans the pumpkin has than the witch, we'll have to subtract the witch's packs of jelly beans from the pumpkin's. This gives us 13. The pumpkin has 13 more packs of jelly beans than the witch. Now that everyone's happy with their treats. What’s that sound? There's a rustling in the bushes. Every man for himself!