Function Machine maths question
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Function Machine maths question
Hi can anyone help with this question from CSSE pass paper. Can't figure out the technique to work out the missing information.
Casey is using a different 'multiply then add' number machine. When she inputs 3, the output is 26. When the input is 6, the output is 36.
3 x ? + ? = 26
5 x ? + ? = 36
Fill in the unknown values for Casey's number machine, so you obtain the same input and output values as she did.
Thanks.
Casey is using a different 'multiply then add' number machine. When she inputs 3, the output is 26. When the input is 6, the output is 36.
3 x ? + ? = 26
5 x ? + ? = 36
Fill in the unknown values for Casey's number machine, so you obtain the same input and output values as she did.
Thanks.
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Re: Function Machine maths question
Is the second input 5 or 6?
Re: Function Machine maths question
Sorry mistake there the second input is 5 not 6.
Thanks
Thanks
Re: Function Machine maths question
I would work out possible answers to the first input, then trial that into the second input
So3x7=21 so you would need to +5 to get to 26. But 5x7+5=40, so that is not correct.
x 6 and+ 8 doesn't work
But x5 and +11 does - 3x5=15 +11=26
and 5x5=25+11=36
So3x7=21 so you would need to +5 to get to 26. But 5x7+5=40, so that is not correct.
x 6 and+ 8 doesn't work
But x5 and +11 does - 3x5=15 +11=26
and 5x5=25+11=36
Re: Function Machine maths question
Or you could use algebra - simultaneous equations
3x+y=26
5x+y=36
from the first equation y=26-3x
put that into the second equation 5x+(26-3x)=36
rearrange 5x-3x=36-26
2x=10
x=5
the put that back into the first equation
3(5) +y=26
y=26-15
y=11
3x+y=26
5x+y=36
from the first equation y=26-3x
put that into the second equation 5x+(26-3x)=36
rearrange 5x-3x=36-26
2x=10
x=5
the put that back into the first equation
3(5) +y=26
y=26-15
y=11
Re: Function Machine maths question
Are simultaneous equations on the year 5 (or year 6) scheme of work in the NC? CSSE doesn't expect any KS3 knowledge (nor should any 11+ exam).2childmum wrote:Or you could use algebra - simultaneous equations
3x+y=26
5x+y=36
from the first equation y=26-3x
put that into the second equation 5x+(26-3x)=36
rearrange 5x-3x=36-26
2x=10
x=5
the put that back into the first equation
3(5) +y=26
y=26-15
y=11
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx
Re: Function Machine maths question
I wouldn't have thought so -although I don't know. I would imagine that the trial method is what the exam is after. I simply put the algebra version in as it is another way to solve it and I though others may be interested. I'll try not to be so helpful next time.
Re: Function Machine maths question
sorry, I appreciate that you may have meant (mainly) how we on here might solve it. However, I did worry slightly that some parents might spend the rest of the holidays making their 10 year olds do algebra after every meal .2childmum wrote:I wouldn't have thought so -although I don't know. I would imagine that the trial method is what the exam is after. I simply put the algebra version in as it is another way to solve it and I though others may be interested. I'll try not to be so helpful next time.
(Having now had a rummage in .gov world, I am relieved to discover that simultaneous equations have not found their way into the KS2 curriculum ).
Outside of a dog, a book is a man's best friend. Inside of a dog it's too dark to read.Groucho Marx
Re: Function Machine maths question
That's ok and I'm sorry for over-reacting. I was just pleased that I had remembered how to use algebra after so many years. And I'm feeling a bit under the weather struggling with a virus which has bought on asthma. I should have stopped before hitting 'submit'
I'm also glad to hear simultaneous equations haven't made it down to KS2 - I stopped teaching a while ago as I could no longer bring myself to put the children through it all.
Hopefully the trial method makes sense.
I'm also glad to hear simultaneous equations haven't made it down to KS2 - I stopped teaching a while ago as I could no longer bring myself to put the children through it all.
Hopefully the trial method makes sense.
Re: Function Machine maths question
Simultaneous equations would definitely not be expected at KS2