School readiness gap
The achievement gap begins early, before students are old enough to enter school. Low-income children lag behind their peers in health; cognitive achievement; language and literacy; mathematical thinking; and physical, social and emotional development before they enter kindergarten. National studies show minority children also lag behind in many of these areas (1).

Math achievement gap
Achievement gaps in math begin in the early years, with differences in math achievement by race/ethnicity and family income status found at kindergarten entry (2).

References:

1. Mueller, D. (2006). Tackling the achievement gap head on. Retrieved from Wilder Research website: http://www.wilder.org/redirects/TacklingtheAchievementGapHeadOn.html

2. Ready Nation. (2013). Tomorrow's science, technology, engineering, and math workforce starts with early education. Retrieved from http://www.readynation.org/uploads//20130318_ReadyNationSTEMBrieflowresnoendnotes.pdf