คิดเลขเร็ว

 $56,212+1,995=.............$  

 $612\times40=.........$  

 $903\times50=..........$  

 $162\div3=................$  

 $246\div6=...........$  

 $891+109+786=.............$  

 $685-\left(214+186\right)=...................$  

 $\left(125+175\right)-100=....................$