According to common sense, the first page is on the right.
Because on the right is page nine.
So the formula: 9- 1=8.
That is, on the left is page 8.
Natural number subtraction:
The subtraction of natural numbers is not closed unless the minuend is greater than the minuend. For example, 1 1 cannot subtract 26.
In this case, one of two methods is used, saying that 1 1 cannot subtract 26; If the answer is an integer indicating a negative number, then 1 1 minus 26 is-15.