Can someone please help me

ok firstly its algebra:

It says think of a number, then add 6, now add the number you were first thinking of, divide by 2, subtract 3

i need this all in algebra

It started off with:

think of a number = n

add 6 = n+6

but i need to know the rest, so what would the rest of it be?

add the number you were first thinking of = ?

divide by 2 =?

subtract 3 = ?

and the answer is the number we were first thinking of, so can you please help?

can you help with this question now please?

a trundle wheel is used to measure distances, a person makes a trundle wheel, of diameter 40cm

what is the circumfrence of the trundle wheel (in cms)?

The person uses the trundle wheel to measure the length of the school car park, the trundle wheel rotates 46 times, what is the length of the car park to the nearest metre?

and it says to use pi in all calculations