Math problem right but wrong

[Khamelion]

Seen this one while perusing the net.

In the US an elementary student was asked to - "Use the repeated addition strategy to solve: 5 x 3"

The student wrote

5x3 = 15 5+5+5

The student had the problem marked as incorrect, the correct answer being stated as 3+3+3+3+3

Was the incorrect answer a bit harsh?

For me, while the student has provided the correct solution, they did not provide the correct answer to the question being asked.

 

[gmhubble]

That reads to me 5 lots of 3

so 3+3+3+3+3 would be correct

 

[ColchesterFC]

That reads to me 5 lots of 3

so 3+3+3+3+3 would be correct

I would read it as 5 times 3, or 5 multiplied by 3, so would say that 5+5+5 is the correct answer.

 

[Rooter]

I would read it as 5 times 3, or 5 multiplied by 3, so would say that 5+5+5 is the correct answer.

Sorry, Disagree. While yes its harsh! I read it as 5 lots of 3. so 3+3+3+3+3

 

[ColchesterFC]

Sorry, Disagree. While yes its harsh! I read it as 5 lots of 3. so 3+3+3+3+3

But there is no such thing as "lots of" in maths. The correct terminology is "multiplied by" which surely means that it is 5 multiplied by 3, or 5+5+5.

 

[Khamelion]

But there is no such thing as "lots of" in maths. The correct terminology is "multiplied by" which surely means that it is 5 multiplied by 3, or 5+5+5.

True, but the equation is asking 5 times of 3, or 3+3+3+3+3, not 3 times of 5 which would be 5+5+5

but on the other hand

The equation is asking 5 multiplied 3 times which would be 5+5+5, had the equation asked for 3 x 5 which would've been 3 multiplied 5 times or 3+3+3+3+3

 

[MegaSteve]

Firstly its arithmetic not maths ...


And, I know from watching/helping grandsons its taught/done a whole lot differently to what I was taught/shown many moons ago...

So, won't presume that I'd know what the correct answer was these days beyond 15...

 

[ColchesterFC]

I should perhaps qualify my answer by saying that it depends on how "the repeated addition strategy", which I haven't heard of before, is taught. If the repeated addition strategy is that it is 5 lots of 3 then the correct answer would be 3+3+3+3+3. The question could be aimed at determining understanding of the strategy more than getting the correct answer of 15.

 

[Khamelion]

Very true, my OP was based on the article I read, I've no idea how the "Repeated addition strategy" was taught in the classroom. The students answer may be factually correct, but given the required answer is something different, the student has either misunderstood what was being taught, not listened in class or applied their own logic to the get an answer.

 

[gmhubble]

5x3 is five lots of three

3x5 is three lots of five

 

[ScienceBoy]

I once got -20 out of 100 in stats exam.

I actually got every question right though...

 

[Crazyface]

5x3 is five lots of three

3x5 is three lots of five

Er... no it's not. The first statement is 5 times three of that's three multiples of 5 and vice versa for the other one.

The lad is correct. But I'm a bloke, as he obviously is, and that's how we see things.

 

[ColchesterFC]

5x3 is five lots of three

3x5 is three lots of five

No it isn't.

5x3 is 5 multiplied by 3 or three lots of five
3x5 is 3 multiplied by 5 or five lots of three

 

[Khamelion]

It all depends on how you read it and the bit we don't know how multiplication has been taught at the school the student is at.

If we read 5 x 3 as 5 multiples of 3 then it writes as 3+3+3+3+3

If we read 5 x 3 as 5 multiplied 3 times then it writes as 5+5+5

 

[Region3]

They should have asked the question about 4 x 4. Save all this malarkey!

 

[SwingsitlikeHogan]

They should have asked the question about 4 x 4. Save all this malarkey!

or just write it in reverse polish notation 5 3 x

 

[USER1999]

Or, just be taught how to multiply, divide, add and subtract. Why does multiplication have to be reduced down to adding?

 

[Deleted member 18645]

How the hell would anyone on this golf forum know what five consecutive 3s are?

 

[Kellfire]

My god. So many people arguing demonstrably incorrect things.

It is 3+3+3+3+3 simply because the rules of repeated addition say that the first number is how many sets you have and the second number is how many are in each set.

How it reads to you is entirely irrelevant as you didn't define the rules!

Stuff like this is embarrassing.

 

[Region3]

How the hell would anyone on this golf forum know what five consecutive 3s are?

Some of us count our putts you know