what is wrong with this please:
;exten => 4,1,WaitExten(3)
exten => 4,1,Set(TOTAL=${MATH(${TOTAL}+500,int)})
exten => 4,n,WaitExten(3)
exten => 2,1,Set(TOTAL=${MATH(${TOTAL}+200,int)})
exten => 2,n,Waitexten(3)
exten => 3,1,Set(TOTAL=${MATH(${TOTAL}+300,int)})
exten => 3,n,WaitExten(3)
exten => 9,1,SayNumber(${TOTAL})