The educational background of students termed "limited English proficient" (LEP) is discussed, with consideration of how that background might affect the LEP student's learning of arithmetic. Reasons why knowledge of background is important are first noted. Then examples of different ways to read and write numerals and differing subtraction and division algorithms are presented, to illustrate how LEP students might have learned to approach arithmetic in ways that differ from those typically taught. Implications of these differences and some specific suggestions for instruction are discussed. Finally, some general conclusions and recommendations are made. (MNS)