Considering the question of addition and subtraction word problems:
Mostly we'll be working with straightforward addition and
subtraction problem types
| Join, Result Unknown |
Jenny had 1/2 of a cup of juice. Her mom gave her another 1/4 cup of juice. How much juice does Jenny have now? |
| Part-Part-Whole, Whole Unknown |
Bill has 1/2 lb of jelly bellies, and 1/4 lb of gummy bears. How much candy does he have altogether? |
| Separate, Result Unknown |
Janet had 3/4 of a foot of bubble tape. She chewed 1/4 of a foot of the bubble tape. How much bubble tape does she have left? |
| Compare, Difference Unknown |
Andy has 3/4 of a bag of M&Ms, and Brenda has 1/2 of a bag of M&Ms. How much more does Andy have than Brenda |
You should notice here, that I have had to use different sorts of objects in my word problems, however. Specifically, almost all of the objects in my word problems are measured amounts of something (so much of a cup, of a pound, of a foot, etc.). I also am pretty careful, every time I tell a fraction, that I tell what it is a fraction of. It is easy to write a word problem thinking it is an addition or a subtraction problem, and find out later that it is much more complicated. If you haven't worked on the the plant problem in the parts and wholes section, you should do so now, before you go on, to see an example of how a problem can be tricky.
These are some tricky problems. Some of them are addion and subtraction problems, but others (about half) are not. think about how you could model each of these using pictures or manipulatives, and then look at my analysis.
1. Ms. Roberts' class had a test in which 1/8 of the students got A's. On the next test, 3/8 of the students got A's. How many of the students received A's on one of the two tests? Analysis
2. It rained 1/2 an inch on Sunday and 2/3 inch on Monday. How many total inches of rain was there? Analysis
3. John ate half of the M&Ms in the package. Later, his sister ate 1/3 of the remaining M&M’s. How many M&M’s are left? Analysis
4. Alice had 3/4 lb. of candy. She gave 1/3 lb. of the candy to Scott. How much candy does she have left? Analysis
5. In Monday, Jane got 4 cookies and half of them were chocolate chip. On Tuesday she got 6 cookies and 1/3 of them were chocolate chip. What fraction of the totalJames cookies she had were chocolate chip? Analysis
6. Mary had 3/4 cup of juice in her glass. She drank 1/3 of it. How much juice is left? Analysis
7. Matthew read 1/8 of a book. Then, after an hour's break, he read 3/8 of the book. How much of the book did Matthew read? Analysis
8. An apple pie was cut into 8 slices. Sally ate 1 slice and Jim ate 3 slices. How many slices did they eat together? What portion of the pie is that? Analysis