计算.5+1+3= 5-3+6=9-6-2= 9-6+7=9-7-2= 6+3-7=7+2-5= 2+5-4=8-3-0= 4-2+5=9-8-1= 10-4+l=
(1)×39 + ×25 + × (2)1×(2 - )+ 15÷
计算: (1)73× (2) 166÷41
计算:(1)×37(2)2004×
计算:
计算:(1998+19981998+199819981998+…)÷(1999+19991999+199919991999…)×1999