(clear-all)

(define-model addition

(sgp :esc t :lf .05)

(chunk-type fraction number denominator numerator)
(chunk-type add arg1 arg2 sum)
(chunk-type mult factor1 factor2 product)
(chunk-type divi dividend divisor quotient)

(add-dm
 (one isa fraction number "2/3" denominator 3 numerator 2)
 (two isa fraction number "1/5" denominator 5 numerator 1)
 (three isa mult fractor1 3 factor2 5 product 15)
 (four isa mult fractor1 5 factor2 2 product 10)
 (five isa mult fractor1 3 factor2 1 product 3)
 (six isa add arg1 10 arg2 3 sum 13)
 (goal isa add arg1 "2/3" arg2 "1/5")