Mental maths

This term we had started a new thing for our mat'hs and literacy contracts i love it so much it helps me more in math's then in literacy.
Sometimes i really don't want to do it but when i have done about six to seven questions I really get into it.
My brain turns all on and i really try my best but when i don't understand it or I don't know the answer to the question we have to highlight it or you can give the answer you think is correct.
Here is a picture of it!!!

We do one column each day until we have finished the four column's
I think everyone in the classroom loves this new active now!!!
Have you ever done mental math's before in your life cause i have????