# Problem Solving…

Tomorrow is one of our favourite lessons in Class 5 – Maths problem solving!

For those of you who want go get into the logical thinking required for this lesson before tomorrow, try this puzzler:

Think of a number
Take 6 away from the answer

What do you notice?
Does this always work? Explain your reasons…

There will be a special prize for some fantastic reasoning. Remember to try lots of different numbers. Please blog your working like you would do in a Maths lesson.

You have until Monday 30rd September to enter your responses. Best of luck guys!

1. Manon

6+3=9
9×2=18
18-6=12
12-6=6

2. Manon

Well I started with 6 and when I finished the whole thing i came back with the number I started with.

3. Ella

2
2+3=5
2×5=10
10-6=4
4 divided by 2=2
in this way you get back to the number you started with but with zero you don’t.

0
0+3=3
3+3=6
6-6=0
but you can’t halve zero.

4. Ella

Actually I’ve worked it out and half of zero is zero!

5. Miss Sawyer

I love your blogs Mr Mastrelli

6. Lewkas Holt

Yes.
When I add 3 and times 2 it makes 6, then minus 6 makes 0.

I just times my number by 2 and then divided by 2.

7. Manon hollingworth

1+3=4 4+4=8 8-6=2 2-1=1
2+3=5 5+5=10 10-6=4 4-2=2
3+3=6 6+6=12 12-6=6 6-3=3
4+3=7 7+7=14 14-6=8 8-4=4
5+3=8 8+8=16 16-6=10 10-5=5

8. class4

I think I’ve worked this out. I love problem solving! I hope you keep putting these problems on here!

Mrs Hearson

9. Owen Oxley

double your original number but double 3 too. Now you have twice your original number plus 6.Take away that 6.

10. Sophie

You always end up with the same number because your basicly doing the oposite to what you’ve already done but in a different order for example:

24+3=27
27+27=54
54-6=48
1/248=24

so it’s always the same number you had.

11. sophia

I tryed…12

12+3=15
15+15=30
30-6=24
Half of 24 is 12
My reasons are…you come back to the number you started with!!

I also tryed…6
6+3=9
9+9=18
18-6=12
half of 12 is 6
you see?

What got you onto maths so much Mr Mastrelli?

12. millie

number 16

16+3=19
double 19=38
38-6=32
half 32=16

13. Lewkas

Yes!
Because two threes make six for example. Double the number, minus six and half of it is the first number you started.

14. Helen

I started with 7 and ended up with 7

15. Betsy

You always end up with the number you started with
eg. I chose the number 5

5 + 3 = 8
8 x 2 = 16
16 – 6 = 10
10 ÷ 2 = 5

you are always add 6 to your number then double the number have now then take away 6 and halve the number

16. Lewkas

My number was 12
12 + 3 = 15
15 x 2 = 30
30 – 6 = 24
24 / 2 = 12

17. Mr Mastrelli

Well done Sophia and Ella, our winners for this blog. Hope you enjoy the pens!

18. Sophia

Thanks Mr Mastrelli! I have been using my pens alot this weekend! They are great.

19. REUBEN

2+3=5 5+5=10 10-6=4 10-10=0

20. Joe

Yes it does work with all the numbers,and I think it is something to do with the fact that you double the 3 which gives you six then you take six away (you are taking away the same number as you are adding). You also double the number then halve it – giving the same number as you had before
(example 12 + 3 (=15) x2 (= 30) – 6 (=24) halve it =12