You can follow the addition learning steps to:
Step1 : 1 ~ 10
Step2 : 10 ~ 100
Step3 : 100 ~ 1000
Step4 : 1000 ~ 10000
Step5 : 10000 ~ 100000
Step1 : 1 ~ 10
Step2 : 10 ~ 100
Step3 : 100 ~ 1000
Step4 : 1000 ~ 10000
Step5 : 10000 ~ 100000
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