690 ants die in 4 days; each nite 35 more die than prev nite; how many died 3rd nite?

Chutney

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Hello, Please help.

Word problem - helping 10 year old.

In an ant colony, 690 ants die in four days.
Each night, 35 more ants die than the night before.
How many ants died on the third night?

Many thanks
 
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Hello, Please help.

In an ant colony, 690 ants die in four days.
Each night, 35 more ants die than the night before.
How many ants died on the third night?

Many thanks
In my opinion, this is an ill-posed problem.

My interpretation of "690 ant dies in four days" - will include dead-ants of fourth night. Then I get fractional ants being killed!!

In previous post you had said that the answers were provided. What was the answer for this problem?
 
Hello, Please help.

In an ant colony, 690 ants die in four days.
Each night, 35 more ants die than the night before.
How many ants died on the third night?

Many thanks
Usually we do not provide complete solution, but rather help students. Since you are trying to help a 10 year I guess that I can help you. Here is a sketch to solve this

35 +70 + 105 = 210---the extra 35's for days 2-4
690-210 = 480

480/4 = 120

120--day 1
120 +35--day 2
120 +70--day 3
120 + 105---day4
 
Hello, Please help.

In an ant colony, 690 ants die in four days.
Each night, 35 more ants die than the night before.
How many ants died on the third night?

Many thanks
We have found that it is very difficult to find out where a child is having difficulties if we do not speak with the child. Please have the child use your identity to speak with us directly so we can find out what the child knows, where exactly the child is having difficulty.
 
Usually we do not provide complete solution, but rather help students. Since you are trying to help a 10 year I guess that I can help you. Here is a sketch to solve this

35 +70 + 105 = 210---the extra 35's for days 2-4
690-210 = 480

480/4 = 120

120--day 1
120 +35--day 2
120 +70--day 3
120 + 105---day4

I appreciate your help. Many thanks.
 
We have found that it is very difficult to find out where a child is having difficulties if we do not speak with the child. Please have the child use your identity to speak with us directly so we can find out what the child knows, where exactly the child is having difficulty.

He finds certain maths word problems difficult. Probability, algebra. Certain questions that tap into deeper thinking.
 
In my opinion, this is an ill-posed problem.

My interpretation of "690 ant dies in four days" - will include dead-ants of fourth night. Then I get fractional ants being killed!!

In previous post you had said that the answers were provided. What was the answer for this problem?

190
 
Correct.

Again I don't think the answer in these sort of questions is as important as the process to get it.

The problem can be solved very easily using algebra, but most 10 year olds aren't quite ready for that yet.

Play around with numbers - so much is gained by playing with numbers.

Guess and check is a legitimate problem-solving technique.

Take a guess.

Let's say the number of dead ants for the 4 days is 100, 135, 170, 205 (increase of 35 each time).

Does this add up to 690? No (it adds to 610). Is it close? (sort of.) Is it too big or too small? (Too small) Do I need to increase or decrease the numbers? (increase)

Ok, so now improve your guess:
1. You could try 110, 145, ...etc and repeat the process OR
2. You could realise that 610 is 80 short of 690, so increase each number in your first guess by 80/4 = 20

(Guessing and checking is an important process for children to go through. It improves basic numeracy, before the big step to more abstract algebra. It also precedes a greater appreciation of algebra, when the time comes, as a tool for solving problems more efficiently.)
 
He finds certain maths word problems difficult. Probability, algebra. Certain questions that tap into deeper thinking.
Did the posted exercise come from an algebra assignment?
 
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