problem solving

[kwg]

Whew I am tired! lol.

 

Ds 10 seems to be having a little trouble with MM 5- Lessons in Problem Solving. I give it to him to do, he gets it wrong, we go over it, he says "oh!". Wash, rinse, repeat. We did some Narnia and Hobbit Math http://letsplaymath....ving-5th-grade/ and he did a little better on those. Any other good practice problems/books I can add in?

[Arcadia]

I'm surprised no one replied. Maybe you can give an example of a question he got wrong. I supplement word problems for my kids from everywhere.

For more practice you can try the questions on (ETA: solutions are on same link)

http://www.risd.k12....oremathbook.cfm

There are also questions and videos on this link (ETA: videos and questions are on the different tabs: addition & subtraction, multiplication & division, fractions and ratios)

http://www.thinkingblocks.com/

[kwg]

I will check out those resources. Thank you!

 

An example of a missed problem:

 

A washer has been discounted by 1/10 of its price, so now it costs $316.80. Another washer has been discounted by 2/5 of its price, and it costs $295.50 now.

Find the price difference between the two washers before the discount.

 

or

 

Brenda and Lily shared the cost of a $11.70 lunch so that Brenda paid two times as much as Lily. Find their shares.

 

I have showed him the bar model way and he hates it. :confused1:

[Arcadia]

Is it because he does not like bar models? Can he solve his own way without bar models? If he just dislike bar models, I'll let him solve whatever way makes logical sense. If he does not understand the bar models, than the videos on the thinkingblocks website would help.

I asked my younger to solve these verbally without working out the answer. This is how he replied.

 

Brenda and Lily shared the cost of a $11.70 lunch so that Brenda paid two times as much as Lily. Find their shares.

1) Divide by 3 to get Lily's share because it is 1/3

2) Times 2 to get Brenda's share

 

A washer has been discounted by 1/10 of its price, so now it costs $316.80. Another washer has been discounted by 2/5 of its price, and it costs $295.50 now.

Find the price difference between the two washers before the discount.

1) divide the price of 1st washer by 9. Then times 10 to get original price

2) divide the price of 2nd washer by 3. Then times 5 to get original price

3) minus the bigger number by the smaller number to get the difference

 

He missed out the word "discounted by" when he read it the first time. He read to me as "A washer 1/10 price is $316.80" on first reading. I asked him to read the question again.

[SnegurochkaL]

A washer has been discounted by 1/10 of its price, so now it costs $316.80. Another washer has been discounted by 2/5 of its price, and it costs $295.50 now.

Find the price difference between the two washers before the discount.

1) divide the price of 1st washer by 9. Then times 10 to get original price

2) divide the price of 2nd washer by 3. Then times 5 to get original price

3) minus the bigger number by the smaller number to get the difference

 

 

 

 

My daughter solves problems like this the same way without really drawing anything.

 

Here is a problem your son might find interesting to solve. My daughter liked it. It is from old Russian math book by L. Magnitsky: " A man wanted to put his son in a class. He asked a teacher how many students were in a class. Teacher replied, " If I get as many students as I currently have and a quarter as many again plus your son, I will have 100 pupils. How many student did teacher have in his class?"

[kwg]

It would be fine if he was getting them correct but he isn't and I am not sure any other way to show it. I think that way I guess. I thought about ordering Singapore Challenging Word problems but looks like the shipping is as much as the book. Thank you for the other suggestions! We will try them!

[Arcadia]

The challenging word problems are nice for extra practice but not cost effective for your current problem.

 

These are easier but might be good just to get use to solving http://www.primaryre...ordproblems.pdf

These are slightly harder http://eclass1.wsd.k...view.php?id=459

 

For general word problems practice, I have used Sunshine Math which is free http://www.lcps.org/Page/57896

[letsplaymath]

A washer has been discounted by 1/10 of its price, so now it costs $316.80. Another washer has been discounted by 2/5 of its price, and it costs $295.50 now.

Find the price difference between the two washers before the discount.

 

or

 

Brenda and Lily shared the cost of a $11.70 lunch so that Brenda paid two times as much as Lily. Find their shares.

 

You might see if he would prefer word algebra. I taught it in the earlier posts in that word problems from literature series, but I really like the bar diagrams, so I shifted toward those as the problems got longer. The basic idea of word algebra is to translate the story into math a little at a time, using words of the story to represent the things you don't know.

 

For instance, if we number the washers #1 and #2:

Price#1 - (1/10) of Price#1 = $316.80

so (9/10) of Price#1 = $316.80

then (1/10) of Price#1 = $316.80 ÷ 9

and finally Price#1 = (that number) × 10

 

Price#2 - (2/5) of Price#2 = $295.50

so (3/5) of Price#2 = $295.50

then (1/5) of Price#2 = $295.50 ÷ 3

and Price#2 = (that number) × 5

 

Or let Brenda's and Lily's names stand for their shares of the cost of the lunch:

Brenda$ + Lily$ = $11.70

and Brenda$ = 2 × Lily$

so (2 × Lily$) + Lily$ = $11.70

etc.

 

If you'd like to learn more about word algebra, these posts start with the basics and work up to an algebra 1 problem:

• Elementary Problem Solving: The Tools
  
• Penguin Math: Elementary Problem Solving 2nd Grade
  
• Ben Franklin Math: Elementary Problem Solving 3rd Grade
  
• Algebra: A Problem in Translation
  

[letsplaymath]

Ed Zaccaro books are also very good for helping children learn to think their way through word problems.