Wykonajmy obliczenia,

Pamiętajmy, że część obliczeń możemy wykonywać "po kawałku".

a)

$37-6=31$  

$59-8=51$  

$33-8=25\left[33-3-5=30-5=25\right]$  

$67-9=58\left[67-7-2=60-2=58\right]$

$94-6=88\left[94-4-2=90-2=88\right]$   

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b)

$43-12=31\left[43-10-2=33-2=31\right]$

$56-25=31\left[56-20-5=36-5=31\right]$   

$68-46=22\left[68-40-6=28-6=22\right]$  

$39-17=22\left[39-10-7=29-7=22\right]$  

$87-43=44\left[87-40-3=47-3=44\right]$  

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c)

$44-35=9\left[44-30-5=14-5=14-4-1=10-1=9\right]$  

$83-77=6\left[83-70-7=13-7=13-3-4=10-4=6\right]$  

$86-39=47\left[86-30-9=56-9=56-6-3=50-3=47\right]$

$71-36=35\left[71-30-6=41-6=41-1-5=40-5=35\right]$   

$92-54=38\left[92-50-4=42-4=42-2-2=40-2=38\right]$  

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d)

$30-2=28$

$80-9=71$

$100-7=93$

$120-9=111$     

$200-6=194$  

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e)

$60-37=23\left[60-30-7=30-7=23\right]$  

$40-23=17\left[40-20-3=20-3=17\right]$  

$90-54=46\left[90-50-4=40-4=36\right]$  

$70-32=38\left[70-30-2=40-2=38\right]$  

$90-16=74\left[90-10-6=80-6=74\right]$  

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f)

$100-35=65\left[100-30-5=70-5=65\right]$  

$100-28=72\left[100-20-8=80-8=72\right]$  

$250-41=209\left[250-40-1=210-1=209\right]$  

$460-56=404\left[460-50-6=410-6=404\right]$  

$590-67=523\left[590-60-7=530-7=523\right]$