NINETY FIRST GRADE CHILDREN WERE RANDOMLY SELECTED FROM 3 SCHOOLS (WHICH EACH USED A DIFFERENT ARITHMETIC PROGRAM) TO PARTICIPATE IN A STUDY TO INVESTIGATE THE EFFECTS OF 2 VARIABLES ON THE CHILDREN'S ABILITY TO SOLVE ADDITION PROBLEMS. THE VARIABLES WERE (1) THE PRESENCE OR ABSENCE OF AN EXISTENTIAL QUANTIFIER PRECEDING THE START OF THE PROBLEM, AND (2) EITHER THE PRESENCE OF 3 DIFFERENT NAMES FOR THE 3 SETS IN ANY PROBLEM OR THE PRESENCE OF COMMON NAMES FOR THE 3 SETS. THE CHILDREN WERE INDIVIDUALLY TESTED ON 20 PROBLEMS WHICH WERE READ TO THEM BY 1 EXPERIMENTER. FORTY-FIVE CHILDREN RECEIVED PROBLEMS WHICH INVOLVED AN EXISTENTIAL QUANTIFIER, AND 45 HAD PROBLEMS WHICH DID NOT. TEN OF THE PROBLEMS GIVEN TO EACH CHILD HAD DIFFERENT NAMES WITHIN THE PROBLEM SETS, AND 10 PROBLEMS HAD THE SAME SET NAMES. ANALYSIS OF VARIANCE OF THE DATA SHOWED THAT THE ONLY SIGNIFICANT DIFFERENCE OCCURRED BETWEEN THE PROBLEMS INVOLVING SET NAMES. ALTHOUGH THE STUDY SCOPE IS LIMITED, RESULTS SUGGEST THAT CHILDREN SHOULD BE GIVEN MORE CHANCES TO INTERPRET PROBLEMS PRESENTED VERBALLY AND THAT PICTORIAL REPRESENTATIONS OF SETS IN EXERCISE BOOKS SHOULD BE DESCRIBED BY DIFFERENT WORDS RATHER THAN BY 1 COMMON TERM. (MS)