口算 + = - = + = &nbs

1. 口算
$\text{[math]}$ + $\text{[math]}$ =        $\text{[math]}$ - $\text{[math]}$ =         $\text{[math]}$ + $\text{[math]}$ =         $\text{[math]}$ - $\text{[math]}$ =
1- $\text{[math]}$ =        $\text{[math]}$ - $\text{[math]}$ =        $\text{[math]}$ + $\text{[math]}$ =        1- $\text{[math]}$ =
0+ $\text{[math]}$ =        $\text{[math]}$ - $\text{[math]}$ =         $\text{[math]}$ + $\text{[math]}$ =          $\text{[math]}$ + $\text{[math]}$ =