(2) through (8). (2) Credit amount Subsection (a) shall be applied by substituting $2,000 for $1,000 . (3) Limitation In lieu of the amount determined under subsection (b)(2), the threshold amount shall be $500,000. (4) Definition of qualifying child Paragraph (1) of subsection (c) shall be applied by substituting 18 for 17 . (5) Partial credit allowed for certain other dependents (A) In general The credit determined under subsection (a) (after the application of paragraph (2)) shall be increased by $500 for each dependent of the taxpayer (as defined in section 152) other than a qualifying child described in subsection (c) (after the application of paragraph (4)). (B) Exception for certain noncitizens Subparagraph (A) shall not apply with respect to any individual who would not be a dependent if subparagraph (A) of section 152(b)(3) were applied without regard to all that follows resident of the United States . (6) Maximum amount of refundable credit (A) In general Subsection (d)(1)(A) shall be applied without regard to paragraphs (2) and (5) of this subsection. (B) Adjustment for inflation In the case of a taxable year beginning after 2017, subsection (d)(1)(A) shall be applied as if the $1,000 amount in subsection (a) were increased (but not to exceed the amount under paragraph (2) of this subsection) 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. Any increase determined under the preceding sentence shall be rounded to the next highest multiple of $100. (7) Earned income threshold for refundable credit Subsection (d)(1)(B)(i) shall be applied by substituting $2,500 for $3,000 . (8) Social security number required No credit shall be allowed under subsection (d) to a taxpayer with respect to any qualifying child unless the taxpayer includes the social security number of such child on the return of tax for the taxable year. For purposes of the preceding sentence, the term