Earthmerlin Posted February 10, 2019 Share Posted February 10, 2019 I need some ideas that use manipulatives in teaching decimals. The concept of decimals, how they relate to fractions, how to round them, how to put them on a numberline. Household items or paper cut-outs are preferred. Candy too! I have Cuisiniere rods too but don't know how I'd use them. I also have Unifix cubes. What else can I grab that's on hand & presents these concepts visually and kinesthetically? Quote Link to comment Share on other sites More sharing options...
wendyroo Posted February 10, 2019 Share Posted February 10, 2019 Money. A dollar is a whole. A dime is a tenth. A penny is a hundredth. 5 Quote Link to comment Share on other sites More sharing options...
wathe Posted February 10, 2019 Share Posted February 10, 2019 (edited) I agree that money is the obvious choice here. Education Unboxed has some nice videos about teaching fractions with C-rods. She also uses money. edited to add link Edited February 10, 2019 by wathe 2 Quote Link to comment Share on other sites More sharing options...
HomeAgain Posted February 10, 2019 Share Posted February 10, 2019 You have c-rods? You can print out base-ten hundred flats (or make them with centimeter graph paper) and do like MUS does, showing that a large plain square is 1, the biggest c-rod is a tenth, and the smallest c-rod is one hundredth. So when you multiply or divide, what you're really doing is taking that small square and breaking it into tenths or whatever, when you have a tenth of a hundredth. You can also show the base number line of how you multiply by whole tens to go to the left, and divide by tens (tenths) to go to the right. Right Start also has brilliant circles to cut out and put together in their E appendix pages. Scroll down to the bottom link here: https://rightstartmath.com/resources/teaching-support/ You can interlock two of the circles to show the relationship between the fractions on one circle, the percentages on another, or swap it out for the decimal one. 1 Quote Link to comment Share on other sites More sharing options...
Earthmerlin Posted February 10, 2019 Author Share Posted February 10, 2019 2 hours ago, HomeAgain said: You have c-rods? You can print out base-ten hundred flats (or make them with centimeter graph paper) and do like MUS does, showing that a large plain square is 1, the biggest c-rod is a tenth, and the smallest c-rod is one hundredth. So when you multiply or divide, what you're really doing is taking that small square and breaking it into tenths or whatever, when you have a tenth of a hundredth. You can also show the base number line of how you multiply by whole tens to go to the left, and divide by tens (tenths) to go to the right. Right Start also has brilliant circles to cut out and put together in their E appendix pages. Scroll down to the bottom link here: https://rightstartmath.com/resources/teaching-support/ You can interlock two of the circles to show the relationship between the fractions on one circle, the percentages on another, or swap it out for the decimal one. I do NOT have base 10 blocks, unfortunately. I'll look at the link you provided though. Quote Link to comment Share on other sites More sharing options...
Earthmerlin Posted February 10, 2019 Author Share Posted February 10, 2019 Money seemed the most obvious place to start & that's what I did today. I had her write dollar, 1/2 dollar, etc. with decimals & I broke down the coins on a homemade tree graphic organizer. Then I had her put coins on number line & note their decimal values below them. I need a next step now, LOL. Quote Link to comment Share on other sites More sharing options...
HomeAgain Posted February 10, 2019 Share Posted February 10, 2019 25 minutes ago, Earthmerlin said: I do NOT have base 10 blocks, unfortunately. I'll look at the link you provided though. Base-ten uses the same scale as the c-rods. You can use the 1cm cube, 10cm rod, and print or cut out 10x10cm flats for hundreds. 1 Quote Link to comment Share on other sites More sharing options...
Sarah0000 Posted February 10, 2019 Share Posted February 10, 2019 For c rods I take a rod, like the 10 one for beginning, and explain this is now a one whole. I relate this to a story like if someone orders 10 pizzas for a party that order is one whole order with ten parts. Then I use a smaller rod, like a 2 rod, and cover up the ten rod and ask what part of the order is completed and how much of the whole is still left to complete. I have my kid write down the fraction, decimal, and percentage. You can use recipes as well. Play dough can be made with (adjusted to make the math easier, if you really make the play dough add a tbsp of cream of tartar and a couple tbsp of oil) 2 parts flour, 1 part salt, 1 part water. How would you write this as decimals? What if a friend comes over and you want to make a double batch what would the decimals (and fractions and percentages) be then? Bonus: if you want to make 12 cups of dough how much of each part do you need? If your daughter is ready then choose a number that does not divide into tenths easily for these parts, like 10 cups of dough, because then you would need a decimal in the thousandths. 1 Quote Link to comment Share on other sites More sharing options...
Earthmerlin Posted February 22, 2019 Author Share Posted February 22, 2019 She is still cloudy on decimals so I need additional ideas please. Quote Link to comment Share on other sites More sharing options...
wendyroo Posted February 22, 2019 Share Posted February 22, 2019 What about having her make a meter stick? Have her cut out 10 pieces of paper, each 10cm x 3cm. Ideally, half of the papers would be one color, and half another. Have her draw the cm divisions on each paper, but don't label them with numbers. In at least one cm on each paper, have her draw the mm divisions as well, but again, just draw the lines, don't number them. Then have her tape the papers together, alternating colors if you used two. Once you have a meter stick, really emphasize that the whole thing is "one whole meter". Then focus in on the alternating colored tenths. Count the tenths. Challenge her to cover 2 tenths with her arm. Cover 3 tenths. Cover 4 tenths. Can she use both hands to cover 1 tenth on either end? How many tenths is she covering total? How many tenths are red? How many tenths are green? What fraction of the meter stick is red? Make sure she really understands that there are 5 tenths that are red...and we can also call that 1/2. What about if each red section buddies up with a green section. Now together 1 tenth + 1 tenth = 2 tenths. What else could we call that fraction? One red + one green is one buddy team out of how many? There are 5 buddy teams, so one red + one green is 1/5 of the whole meter. 2/10 = 1/5. Before you move on to centimeters, make sure you focus on the place value of tenths. Write a number like 123. Talk about what it means in terms of meters. That distance is made up of 100 meters + 20 more meters + 3 more meters. Now add to the number so it looks like: 123.4. Really make sure she understands that the 4 is in the tenths column. Just like the 1 tells how many hundreds of meters, and the 2 tells how many tens of meters you have to add to that, and the 3 tells how many individual meters you have to add to that, the 4 tells how many tenths of meters you have to add to the whole meters you already have. Practice saying numbers in extended form: 3698.2 = three thousands, 6 hundreds, 9 tens, 8 ones, and 2 tenths. 8003.6 = eight thousands, 3 ones, and 6 tenths. Make sure to deal with zeros in certain place values now, so she will have a basis when she needs to work with numbers like 1.03. While you are talking about place value, introduce the hundredths place. Get her comfortable expressing numbers like 1234.56 and 9876.05 in extended form. Make sure she really "sees" that .56 is BOTH 5 tenths plus 6 more hundredths AND 56 hundredths. Relate it back to integer numbers. 37 can be expressed as 3 tens and 7 more ones OR as 37 ones. You need to be able to switch fluidly back and forth. To really hammer home hundredths, I would then put one M&M on each cm of the meter stick. BUT, I would rig the deck ahead of time to ensure that there were less than 10 M&M of one color (so she is forced to deal with a number like .06) and a multiple of ten of another color (so she is forced to deal with a number like .20 = .2). On a separate piece of paper, I would draw a number line from 0 to 1 and have her label the tenths. Then have her count each color of M&M and mark it on the number line. So, greens might be .06, so she needs to envision where 6 hundredths would fall on the number line. If she struggles, start at 0, and start pretending to count hundredths even though they are not marked. Keep going until you count 10 hundredths at the .1 line and 20 hundreds at the .2 line...and keep going if she needs to. Do the rest of the colors. Where would .24 be? Where would .30 be? After you get the colors on there, start labeling red + brown and green + yellow and all the other combinations until she is confidently adding the decimals and marking them on the number line. Then I would eat the M&Ms. The last thing I would cover with the meter stick is thousandths. She marked some mm, so talk about how actually each cm is comprised of 10 mm, and that total there are 1000 mm in the one meter. Add thousandths to your place value chart and practice saying 1234.567 in extended form. Then practice 2345.006 and 3456.078 and 4567.809. Find each of those decimal components on the meter stick. For example, one mile is 1609.344 meters; so emphasize that you would have to lay out 1000 of your meter sticks, plus 6 hundred more, plus 9 more, plus .344 more. Just like she covered .2 and .3 and .4 of the meter stick at the beginning, now have her cover .344 of the meter stick. Have her find .344 on her M&M number line. Have her change .344 into a fraction. Have her figure out how far 2 miles would be and then find .688 on her meter stick and number line.Since her M&M number line is only marked with tenths, it should be very sketchy pinpointing a thousandths decimal on the line. That is good because it makes her think, and it also would segue nicely into talking about rounding .344 down to .34 or .3 and .688 up to .69 or .7. Wendy 2 Quote Link to comment Share on other sites More sharing options...
Rosie_0801 Posted February 23, 2019 Share Posted February 23, 2019 We used the CSMP minicomputers for a lot of that. Quote Link to comment Share on other sites More sharing options...
Lori D. Posted February 23, 2019 Share Posted February 23, 2019 Not manipulatives, but the Key to ... series were helpful for DS#2 for solidifying decimals, percents, and fractions. Each topic has a series of workbooks, and shows the concept from a variety of angles. I was surprised but pleased that our very visual-spatial/math struggling DS#2 clicked well with these. 1 Quote Link to comment Share on other sites More sharing options...
PeterPan Posted February 25, 2019 Share Posted February 25, 2019 On February 9, 2019 at 9:23 PM, Earthmerlin said: The concept of decimals, how they relate to fractions, how to round them, how to put them on a numberline. Household items or paper cut-outs are preferred. Can she do all those skills with fractions? And have you done them parallel? (matching memory game with fraction and decimal quantities, the number lines run parallel, etc.)? 1 Quote Link to comment Share on other sites More sharing options...
Ausmumof3 Posted February 25, 2019 Share Posted February 25, 2019 Place value discs? I need to review this with mine now. 1 Quote Link to comment Share on other sites More sharing options...
Earthmerlin Posted March 2, 2019 Author Share Posted March 2, 2019 Thanks, folks! We're making some progress! Now, any simple but concrete ideas on converting fractions to decimals & vice versa? Quote Link to comment Share on other sites More sharing options...
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