You only enter the business income & expenses on the schedule C or C-EZ. Then the Net Profit or Loss from Schedule C automatically goes to 1040 line 12. Only enter anything only 1 time and only in 1 place.
1040 Line 40 is your personal Standard Deduction (I posted the amounts above) or your personal Itemized Deductions from Schedule A. Completely different and separate from schedule C business.
Here is 2016 Schedule C-EZ
https://www.irs.gov/pub/irs-prior/f1040sce--2016.pdf
Here is 2016 full Schedule C
https://www.irs.gov/pub/irs-prior/f1040sc--2016.pdf
And Schedule A
https://www.irs.gov/pub/irs-prior/f1040sa--2016.pdf
