24 of the Internal Revenue Code of 1986 is amended by inserting after paragraph (2) the following new paragraph: (3) Limitation (A) In general The amount determined under paragraph (1)(A) with respect to any qualifying child shall not exceed $1,400, and such paragraph shall be applied without regard to subsection (h). (B) Adjustment for inflation In the case of a taxable year beginning after 2018, the $1,400 amount in subparagraph (A) shall be increased by an amount equal to— (i) such dollar amount, multiplied by (ii) the cost-of-living adjustment determined under section 1(f)(3) for the calendar year in which the taxable year begins, determined by substituting 2017 for 2016 in subparagraph (A)(ii) thereof. If any increase under this clause is not a multiple of $100, such increase shall be rounded to the next lowest multiple of $100. . (e) Earned income threshold for refundable credit Section 24(d)(1)(B) of the Internal Revenue Code of 1986 is amended by striking $3,000 and inserting $2,500 . (f) Social Security number required Paragraph (1) of section 24(e) of the Internal Revenue Code of 1986 is amended to read as follows: (1) Qualifying child Social security number requirement No credit shall be allowed under this section to a taxpayer with respect to any qualifying child unless the taxpayer includes the name and social security number of such child on the return of tax for the taxable year. For purposes of the preceding sentence, the term social security number means a social security number issued to an individual by the Social Security Administration, but only if the social security number is issued— (A) to a citizen of the United States or pursuant to subclause (I) (or that portion of subclause (III) that relates to subclause (I)) of section 205(c)(2)(B)(i) of the Social Security Act, and (B) before the due date for such return. . (g) Repeal of deadwood (1) In general Section 24 of the Internal Revenue Code of 1986 is amended by striking subsections (i) and (j) and by redesignating subsection (k) as