in the case of the dollar amount contained in paragraph (5)(B), 1997 . (B) Rounding If any increase under subparagraph (A) is not a multiple of $50, such increase shall be rounded to the next lowest multiple of $50. . (c) Conforming amendment Section 63(c) is amended by striking paragraph (7). (d) Effective date The amendments made by this section shall apply to taxable years beginning after the date of the enactment of this Act. 122. Increase in and modification of child tax credit (a) In general Section 24 is amended by striking subsections (a), (b), and (c) and inserting the following new subsections: (a) Allowance of credit There shall be allowed as a credit against the tax imposed by this chapter for the taxable year an amount equal to the sum of— (1) $2,000 for each qualifying child of the taxpayer, and (2) $500 for each qualifying dependent (other than a qualifying child) of the taxpayer. (b) Limitation based on adjusted gross income The amount of the credit allowable under subsection (a) shall be reduced (but not below zero) by $50 for each $1,000 (or fraction thereof) by which the taxpayer's modified adjusted gross income exceeds $400,000 in the case of a joint return ($200,000 in any other case). For purposes of the preceding sentence, the term “modified adjusted gross income” means adjusted gross income increased by any amount excluded from gross income under section 911, 931, or 933. (c) Qualifying child