When dividing the students into teams, use the terms that represent their portion of the class, "green 1/2" or "blue 1/4" etc., or build from there; "this is 1 of the 2" or "this is 1 of the 4" etc. while pointing to the numbers representing those fractions.  As music educators we introduce fractions long before the math curriculum.  The example above is great WHEN putting the numerical fraction beside the note of the same. 

Don't forget to do the same for ALL TIME SIGNATURES, 6/8 is really six divisions of 8ths, 3/4 is three divisions of quarters or 4ths.  We usually don't start this until 4th grade, although from 1st grade we learn that the top number tells us how the beats are being MEASURED (a first grade math concept) by the barlines, and this is reinforced EVERY TIME we count the beats of a song, which is every song we learn, K-5th. 

The second grade covers liquid measurements - gallon, half, quart, pint, cup - these are equal to our whole, half, quarter, eighth, sixteenth.  A chart showing one should be right  beside a chart of the other.  Oh, the example above works best if used EVERY TIME, EVERYDAY, EVERY GRADE.  The repetition alone is worth volumes, especially to the LD students.  How about a body made from a HUGE whole note, or two, torso of a half note, head of the other half, arms/legs of quarters, fingers of eighths, hair of sixteenths....looks pretty funny, but, catches the eye, and memory!