叫互为倒数.举例如: 和 .
我会填. (1) = = ; (2) =﹣ = .
在横线里填上合适的数. (1)+ = (2)+ =1 (3)﹣ = (4) ﹣=0.
看图写算式. (1) + + = . × = (2) + = = . × = = (3) + + + = . × = .
+=+= .(判断对错)
﹣= 想: 个减去 个得 个,就是 .