thowell Posted January 23, 2012 Share Posted January 23, 2012 Ok dd11 is using Systematic Mathematics. Here is the question A boys club raised money. They spent 3/5 of the money they raised on food, a total of $17.10. How much money did they raise? How much money was left? The answer is $28.50 and $11.40 left. How does she write this equation? They have taught her to write things like this Ex. 3 is what part of 12 would be the same as 3 = ____ x 12 or what part of 30 is 1/8 would be the same as _________ x 30 = 1/8 I can not for the life of me figure out how to make her understand how to write the equation for this word problem. Thanks for any help!! Quote Link to comment Share on other sites More sharing options...

Dana Posted January 23, 2012 Share Posted January 23, 2012 3/5 (money) = spent Translation for 3/5 of money was spent on food. Then put in numbers. Using words first is often very helpful in figuring out where numbers should go. Quote Link to comment Share on other sites More sharing options...

8filltheheart Posted January 23, 2012 Share Posted January 23, 2012 Has she learned ratios? It is a very simple ratio problem to set up if she has. 3/5 of the money raised = $17.10/total amt of money Then it is simply a matter of cross multiplying/dividing. Another explanation for the same process would be that if 3/5 = $17.10 than dividing 17.10 by 3 is the equivalent of 1/5 and working from there. HTH Quote Link to comment Share on other sites More sharing options...

ChrissySC Posted January 23, 2012 Share Posted January 23, 2012 (edited) Well, we would bar graph this. :) Thanks to MM. Total for food was 17.10, which was 3/5 of the money. |____|____|____|____|____| |______________| 17.10 |____| 5.70 (divided 17.10 by 3) For that matter, 5.70 X 5 = 28.50 And, 5.70 + 5.70 = 11.40 Another way of doing this is the chart method, also taught in MM ... 1-5.70 2-11.40 3-17.10 4-22.80 5-28.50 Edit: I read your post again. I think that they want you to use this .... x of y is z "Of" means multiplication * "Is" means equals = 3/5 * x = 17.10 Edited January 23, 2012 by ChrissySC Quote Link to comment Share on other sites More sharing options...

thowell Posted January 23, 2012 Author Share Posted January 23, 2012 Ok, thanks we have it. I just think the way they explain it is a little confusing. Quote Link to comment Share on other sites More sharing options...

Poke Salad Annie Posted January 24, 2012 Share Posted January 24, 2012 (edited) I would set it up like this: 3:5 = 17.10:n (multiply outers and inners :), a silly jingle I learned way back when) So, 3 x n = 5 x 17.10 3n = 85.50 n =28.50 So, the total amount is $28.50. Then subtract the $17.10 from the total ($28.50) and get $11.40. When I took algebra many moons ago, I was taught to set those kinds of problems up as ratios and proportions. (Remember, a proportion is a statement that two ratios are equal.) It helped me tremendously to see how the numbers compared to each other that way. In other words, I would see this as 3 is to 5 as 17.10 is to what number (n). Edited January 24, 2012 by Poke Salad Annie Quote Link to comment Share on other sites More sharing options...

Marylou Posted January 25, 2012 Share Posted January 25, 2012 I would set it up like this: 3:5 = 17.10:n (multiply outers and inners :), a silly jingle I learned way back when) So, 3 x n = 5 x 17.10 3n = 85.50 n =28.50 So, the total amount is $28.50. Then subtract the $17.10 from the total ($28.50) and get $11.40. When I took algebra many moons ago, I was taught to set those kinds of problems up as ratios and proportions. (Remember, a proportion is a statement that two ratios are equal.) It helped me tremendously to see how the numbers compared to each other that way. In other words, I would see this as 3 is to 5 as 17.10 is to what number (n). Ooooh. I am so gonna steal this! Thanks! Quote Link to comment Share on other sites More sharing options...

silliness7 Posted January 25, 2012 Share Posted January 25, 2012 We would draw a rectangle to represent the total earned. Then we would divide the rectangle into 5 pieces. 3 of those pieces total 17.50. If you can figure out what one piece is you've got it made. Generally from there they should see that 17.50 divided by 3 will give them the value for one of the pieces or 1/5. Then the illustration makes it very easy to see that you add all the 1/5 pieces together to get the total. And you add the 2 pieces not colored in to get what was left. I tell my kids when in doubt, draw a picture. Quote Link to comment Share on other sites More sharing options...

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