Why the new 12000 dollar standard deduction for single, and 24000 for joint in the new tax plan is

[sl8]

49. No, the exemptions are line 6a-d (and line 42)

From the 2016 1040 instructions,
https://www.irs.gov/pub/irs-pdf/i1040gi.pdf

Line 40
Itemized Deductions or
Standard Deduction

In most cases, your federal income tax
will be less if you take the larger of your
itemized deductions or standard deduc-
tion.

Itemized Deductions

To figure your itemized deductions, fill
in Schedule A.

Standard Deduction

Most people can find their standard de-
duction by looking at the amounts listed
under “All others” to the left of line 40.

Exception 1—dependent. If you, or
your spouse if filing jointly, can be
claimed as a dependent on someone
else's 2016 return, use the Standard De-
duction Worksheet for Dependents to
figure your standard deduction.

Exception 2—box on line 39a checked.
If you checked any box on line 39a, fig-
ure your standard deduction using the
Standard Deduction Chart for People
Who Were Born Before January 2,
1952, or Were Blind.

Exception 3—box on line 39b
checked. If you checked the box on
line 39b, your standard deduction is
zero, even if you were born before Janu-
ary 2, 1952, or were blind.

(Bold added by me - sl8)

Line 39a modifies the standard deduction.

Edited to include more of instructions, added bold.