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## 6th grade

### Unit 6: Lesson 6

Expression value intuition# Expression value intuition

In an expression like 2x+7, the value of x can change. As the variable increases and decreases, what happens to the value of the expression?

### Make sure you understand the question that Sal solved.

## Let's try some practice problems!

## Want to join the conversation?

- Can any of you guys can help me with this? I am really struggling with this topic. Please help...(6 votes)
- What part of it do you not understand? If it's all of it, you should probably go to previous lessons, and study a bit more. If there's a particular section you don't understand, or a part where it gets confusing, then we can better help you.(1 vote)

- Why does it stay the same? It would decrease because it's a division problem. How does it stay the same?(4 votes)
- 2t divided by t is the same as 2 - the t on top and bottom can 'cancel' each other out (as they'll grow at the same rate).

It's a tricky one and will become more apparent as you go further through the Algebra syllabus here!(3 votes)

- Hi guys, I just wanted to understand the goal of this particular lesson...

I am in no way trying to be cynical, but, serious

What's the point of this?

Do we memorise this?

i.e.

"When you are subtracting a variable that it is Increasing, the expression Decreases"

"When you are dividing by a variable that decreases but still remains a whole number, the expression Increases"

"When you are dividing an increasing variable by itself, as long as it is a whole number, regardless of the value of the Variable, the answer will always be the coefficient divided by the coefficient" - in which case the usage of the variable becomes obsolete.

Please explain,

Thank You(5 votes)- It gets you thinking about numbers, variables and their relationship. As you go further into the algebra playlist, it becomes apparent.(2 votes)

- i still don"t understand the concept. Hope someone can help me simplify it to my understanding(3 votes)
- it hard but not that much(3 votes)
- The video says, and the table shows, that the last problem would stay the same, yet the system markd this response as incorrect. It says that 2(t/t) decreases. Does anyone know why?(3 votes)
- I just tried it. I selected "stays the same" and it was marked correct.(2 votes)

- This makes no logical sense. If k=1 then 1+35=36, If k=2 then 2+35=37. both numbers are increasing. Yet the right answer is that it decreases. The explanation isn't really an explanation but a string of numbers. How could these numbers be decreasing? The second expression of the exercise says it decreases also but yet the expression is now 30-3a. I find there's no pattern regardless if the expression is addition or subtraction.(3 votes)
- I believe you are getting confused. The question is asking what will happen to k or a when their values are changed. Number k’s value is decreasing, so the overall sum is going to get smaller. Number a is a little different though, because now we are increasing the value of the subtrahend (the number that is subtracting the minuend), so the value will decrease. The questions are a little confusing so you might need to understand what exactly the question is telling you.(1 vote)

- i neeed help also because i have no idea if it increases or decreses(2 votes)
- Me neither. I mean, I get the concept but it is just little confusing.(2 votes)
- How come it stays the same?(1 vote)
- 2t/t is the same as 2/1 * t/t. No matter what t is, the ratio is the same i.e. 2.

ex1: t=5 - 2/1 * 5/5 = 10/5 which simplifies to 2/1 which is 2.

ex2: t=10 - 2/1 * 10/10 = 20/10 which simplifies to 2/1 which is 2.(1 vote)