动脑筋哦
观察下面算式,你发现了什么?
2/1=1*2/1=1-2/1
6/1=2*3/1=2/1-3/1
12/1=3*4/1=3/1-4/1
请你计算:
2/1+6/1+12/1+20/1+30/1+42/1+56/1
(“/”代表分数线)
参考答案:2/1+6/1+12/1+20/1+30/1+42/1+56/1
=(1-2/1) + (2/1-3/1)+(3/1-4/1)+(4/1-5/1)+(5/1-6/1)+(6/1-7/1)+(7/1-8/1)
=1-8/1
=8/7
观察下面算式,你发现了什么?
2/1=1*2/1=1-2/1
6/1=2*3/1=2/1-3/1
12/1=3*4/1=3/1-4/1
请你计算:
2/1+6/1+12/1+20/1+30/1+42/1+56/1
(“/”代表分数线)
参考答案:2/1+6/1+12/1+20/1+30/1+42/1+56/1
=(1-2/1) + (2/1-3/1)+(3/1-4/1)+(4/1-5/1)+(5/1-6/1)+(6/1-7/1)+(7/1-8/1)
=1-8/1
=8/7