Last week we worked on Percent of a Number and introduced Singapore Math in which you use modeling and illustrations. For example: What is 20% of 80. Make 100% 80 and encourage students to use knowledge of benchmarks (50%, 25%, 10%, 5%, and 1%) to get to 20% (10% x 2, 5% x 4, 1% x 20, etc.). You can also use this when you start with proportions.
Currently I am teaching the consumer apps unit involving discount and sales price, tax, tip, mark up and mark down. The most important piece I believe is vocabulary. I was amazed that the students had no idea that discounts save us money and tax adds to our total. We use the same concept of benchmarking and the Singapore math to find discount, etc. Also it helps if students understand that if there is a 30% discount I am only paying 70%. So if they know 10% they can multiply by 7 and get the 70% and still figure out how much they will pay.
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I am starting the same unit at the end of next week. I would be interested in learning more about the Singapore Math as this is the first I have heard of it. I also agree with your comment about the students level of understanding of the basic vocabulary. That needs to be a critical part in making this unit successful. Good luck and thanks for the tips.
ReplyDeleteI taught this unit to my 7th graders last year and I had the same exact problems with basic vacabulary as you did. For this unit, I found that it is very helpful to teach students to underline the key words for each question, such as the discount amount, total price etc. Also, I used the is/of = %/100 formula. Some of my students found it easier to solve the problems using this formula.
ReplyDeleteLast year, I focused more on process than on concept and taught how to solve sales tax, tip, discount, and simple interest problems. This year I am focusing first on percent of a number and then into the process for problem solving. I agree with the vocabulary thoughts. My students would have been able to eliminate so many wrong answers if they understood last year that discount saves money, tax is added, etc. If anyone can post a good link for the Singapore MAth, I would like to learn more.
ReplyDeleteI have used the Singapore method for the first time this year. Some students have really taken to it. I leave them all the option of also solving consumer app type problems by using proportional reasoning, but I have been pleasantly surprised at how many kids like using the benchmarks and number manipulation strategies involved in using the Singapore method- Don Lloyd
ReplyDeleteI am like Mr. Swain I have not heard of this "Singapore Method" before and would love to know more about it! When I taught this unit last year the students really struggled with the vocabulary and I will focus this year more on the is/of concept.
ReplyDeleteI don't know anything about Singapoer Math but I love to teaching this unit because I find it is one of the most useful application s kids will use. Make sure they have a stong back ground in proportions.
ReplyDeleteFor your reading enjoyment, here's the sequence of lessons on Percentage in Singapore Math, US Edition 6A:
ReplyDelete-Express part of a whole as a fraction or percentage.
-Express a fraction as a percentage.
-Express a percentage as a fraction in its simplest form.
-Express a decimal of up to 3 decimal places as a percentage and a percentage as a decimal.
-Solve word problems involving percentage.
-Find the percentage of a percent.
-Review the meaning of tax, percent increase, percent decrease, interest and discount. Solve word problems.
-Express one quantity as a percentage of another using the fraction method.
-Express one quantity as a percentage of another using the unitary method.
-Find percent increase, percent decrease and discounts. Relate selling price to cost price as percentage.
-Find amounts when given their increase or decrease in percentage.
-Find the whole when given the value of a percentage part, using a unitary method.
- Find an original value when given a new value after its percent increase or decrease. Find the new value when given the original value and a percent increase or decrease.
-Solve problems which involve percentage by using the unitary method.
You can find full scope & sequences, articles and plenty more information at http://singaporemathsource.com and http://www.singaporemath.com
We're getting ready to start this unit and in the past I have had problems with vocabulary. I'm thinking I might have the students underline anything that is taken away in (discount, sale price) in blue and anything that is added (tax, markup, interest) in red.
ReplyDelete