Mathematics 2

A 30 cm is a foot
Where I know that 2.54 is an inch.
I know I had to be reaching a full
But still a 30 inch I simply fail.
I ask my brain if a 15 is a foot
Or maybe a 30 inch is still a foot
Mind you it was a ruler I thought
A foot was definitely a 30 in cm
But how much in an inch I fail.
I thought and thought
And there it was
Surely a 15 inch would make a foot
But I have always known it hasn't
I look for the number and then more.
Some tell me its the good old 12
And I know it sure is.
Why can't I meet the 12?
When I was always so true.
Again,
Understanding this struggle
Is in the pace-
a struggle my brain seem to face.