解题思路:(1)因为1+2=3,3÷3=1;据此解答即可;
(2)因为1×2=2,2+3=5,5-4=1;据此解答;
(3)1+2=3,3×3=9,9-4=5,5÷5=1;据此解答.
(1)(1+2)÷3,
=3÷3,
=1;
(2)1×2+3-4,
=2+3-4,
=1;
(3)[(1+2)×3-4]÷5,
=[9-4]÷5,
=1;
故答案为:(+),÷;×,+,-;[(+),×,-],÷.
点评:
本题考点: 填符号组算式.
考点点评: 观察题干,综合分析数字以及运算符号的特点进行解答.
解题思路:(1)因为1+2=3,3÷3=1;据此解答即可;
(2)因为1×2=2,2+3=5,5-4=1;据此解答;
(3)1+2=3,3×3=9,9-4=5,5÷5=1;据此解答.
(1)(1+2)÷3,
=3÷3,
=1;
(2)1×2+3-4,
=2+3-4,
=1;
(3)[(1+2)×3-4]÷5,
=[9-4]÷5,
=1;
故答案为:(+),÷;×,+,-;[(+),×,-],÷.
点评:
本题考点: 填符号组算式.
考点点评: 观察题干,综合分析数字以及运算符号的特点进行解答.