Rounding decimals is going to the dogs with this set of task cards and printables designed to help your students practice rounding decimals to a variety of places. The 32 task cards, 2 journal inserts, and 4 assessment activities in this set are the perfect tools for developing and assessing your students’ understanding of decimal relationships.
Common Core State Standards for Mathematics addressed:
Numbers and Operations in Base Ten (5.NBT)
Understand the place value system.
• Use place value understanding to round decimals to any place. (5.NBT.4)
These cards are designed to help students round decimals, and they require students to round decimals to the nearest whole, tenth, hundredth, and thousandth. I set up the cards to build student understanding of number relationships as well as to allow for easy differentiation.
• 2 graphic reference sheets
• 32 task cards
• answer sheet and key
• four one-page assessment activities (scoring guides included)
About the Cards
The first sixteen cards present students with a number line to help guide their thinking as they round the numbers. The endpoints of the number lines match the place to which the number has to be rounded. When I am teaching rounding, I prefer to emphasize number relationships, rather than focusing attention on individual digits out of context of the number as a whole. Number lines play an important role in my classroom when rounding, and so they feature prominently in these cards. Rather than telling them , “Go to ____ place, see if it is less than 5 or 5 and above, then…”, I am more likely to ask, “Which numbers does this fall between? Which is it closer to?”
For Cards 1-8, the provided number lines have both endpoints as well as the midpoint marked and labeled. Students can use the number line to determine to which of the endpoints the given decimal is closer. The number lines also reinforce that there are
indeed numbers that come between, for instance, 3.62 and 3.73 (and that the midpoint of those numbers is not 3.62 1/2 or 3.62.5 as my students often suggest!). Cards 9-16 also present number lines, though these number have only the endpoints labeled, not the midpoint. For these cards, part of the work the students will have to do is determine the mid-number of the number line. Once they do that, rounding the number will be simple!
The second half of the set, cards 17-32, do not feature number lines. When solving these, students may draw their own number lines in their journal, or they may be able to simply visualize a number line and recognize the decimal to which the given number rounds.
I know from experience that students have an easier time rounding whole numbers to the highest place than rounding to a place other than the highest one. A similar challenge presents itself when my students work with rounding decimals. I have found that they can more easily round decimals when they are rounding one place to the left (for instance, rounding 3.18 to the nearest tenth) than when there are “extra places” (like when rounding 3.1842 to the nearest tenth). I organized the questions based on whether the students are asked to round to the “next place over” or not. All of the odd-numbered cards require students to round to the “next place over”, while the even-numbered cards present students with decimals that have “extra places” that they will have to ignore when rounding.
Practicing the Concept
There are lots of ways in which you can implement the task cards. You can have the students work on them independently, working through the task cards on their own. The students can work on them in pairs or small groups, completing all the task cards in one session. You can use them in centers, having the students complete 6-8 task cards a day over the course of the week. You can even use them as a variation of “problem of the day”, giving each student 1 sheet of 4 cards (or even cutting the sheet in half to give them 2 even-numbered cards or 2 odd-numbered cards) and having them glue in their journals and solve.
The format and order of the cards allows you to more easily differentiate for the needs of your students. You can have some of your students work on the cards with number lines first and then move to the cards without number lines, while others begin with card 17 and work just with the cards without number lines. Alternately, you can have some (or all) students work on just the odd-numbered cards first, and when you feel they are ready to round to a place other than the “next place over”, have them complete the odd-numbered cards. You might choose to do odd-numbered cards one day and save the even-numbered cards for another day. You might even have some students do just even-numbered cards, assign just odd-numbered cards to other students, and have some students do all the cards.
When grading the answer sheet, you can use the odd-even structure to see if there are any patterns to the students’ incorrect answers. Does a student have more incorrect answers for even-numbered cards than odd-numbered cards? If so, that student needs to practice with figuring out which place is important to examine when rounding to, for instance, the nearest tenth.
Included in this set are eight “answer cards” that can serve as a resource if you use a self-paced structure for implementing the task cards. Often, I would have kids work in pairs on cards while I circulated to spot check and give feedback to pairs of students. Naturally, I would get backed up and not be able to reach as many kids until after they had already made many mistakes. I designed these answer cards so that the students could check themselves: catching errors, figuring out for themselves what they did wrong, and (hopefully) avoiding the same mistake on later cards.
Reinforcing the Concept
Included among the printables are two handy reference sheets, perfect for your students’ math notbooks. The first graphic reference sheet is full page and demonstrates how a number line can be used to round a decimal to the nearest tenth, hundredth, and thousandth. The other reference is a flip-book that your students can cut out and glue in their journal. There are two different versions of the flip-book, and you can choose which of the two to use with your students. The first flip-book is a complete reference. It shows and describes how a given decimal can be rounded to the nearest tenth, hundredth, and thousandth, using number lines to show which tenth, hundredth, and thousandth the decimal is nearer. The second version is more of an interactive resource as it is designed to be completed with your students. The students are given a specific decimal to round and the flaps present incompletely labeled number lines and cloze sentences that the students complete as they think through how the given decimal can be rounded. Before you have your students complete the cards, you can have them glue either or both references in their journals. Your students can use the journal inserts as guides while they work on the cards, as well as when they complete other tasks that relate to place value.
Assessing Student Understanding
The four provided assessment activities can be used to evaluate student understanding of the rounding decimals to tenths, hundredths, and thousandths. The activities were designed in pairs, and the two activities in each pair are formatted similarly, and have similar types of questions, though the numbers on each are different. The first two activities assess decimal rounding in a straightforward manner, asking students to round decimals to the nearest tenth, hundredth, and thousandth. The second two are a little more challenging, asking students to round and sort different decimals and then to show how a number line can be used to round a given decimal of their choice. You can use these activity sheets in a variety of ways. You could give one as a pre-test, then teach your lesson and allow students to practice with the task cards, and then give the second worksheet as an independent post-test. You could also have the students work on the task cards, then complete one of the worksheet as guided practice with yourself, a partner, or a small group, and then give the second worksheet as an independent assessment. The worksheets could also be given as homework, center assignments, or any other purpose that fits your teaching style or classroom routines.
For more practice with decimal and place value concepts, please check out the other related resources I have available –
Dog-Gone Decimals – decimal estimation task cards & printables (set b)
Super Powers of Ten - task cards + printables (set a)
Placing the Value - task cards + printables set
Self-Checking Math Riddles – Comparing Place Values: 10x Larger and 10x Smaller
I hope your students enjoy these resources and are able to build their understanding of decimal relationships. – Dennis McDonald