Understanding Mathematics, Resource 2, Chapter Nine.
6. If I think of a number, halve it, take away 5 and then add on 3 times the
number I thought of I end up with a number that is 4 more than twice the
number I first thought of. What was the number I first thought of?

7. I think of a number and add it to twice itself. If I then take away one less
than the number first thought of I end up with an answer of 9. Find the
number first thought of.

8 I think of a number, add 4 and then multiply the answer by 5. I could
have achieved the same final answer had I instead multiplied my chosen
number by 4 and then added 5. What was the number I thought of?

9. If I take a particular number from 3, double the answer and take the
result of doing this from the answer obtained by multiplying the particular
number by 3 and adding 15, I end up with 25. What is the particular
number I started with?

10. I think of a number, add three, divide the answer by 2 and then add 7
This gives an answer that is the same as I would have obtained had I
instead doubled the number first thought of and then taken away 8. Find
the number first thought of

Pls answer whichever you can do!