سرعت انتقال و محاسبات ذهنی -

0×9+1=1




1×9+2=11





12×9+3=111





123×9+4=1111





1234×9+5=11111





12345×9+6=111111





123456×9+7=1111111





1234567×9+8=11111111





12345678×9+9=111111111

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1×8+1=9





12×8+2=98





123×8+3=987





1234×8+4=9876





12345×8+5=98765





123456×8+6=987654





1234567×8+7=9876543





12345678×8+8=98765432





123456789×8+9=987654321

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9×9 =81




99×99 =9801





999×999 =998001





9999×9999 =99980001





99999×99999 =9999800001





999999×999999 =999998000001





9999999×9999999 =99999980000001

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999999×2=1999998​

999999×3=2999997





999999×4=3999996





999999×5=4999995





999999×6=5999994





999999×7=6999993





999999×8=7999992





999999×9=8999991

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0×9+8=8





9×9+7=88





98×9+6=888





987×9+5=8888





9876×9+4=88888





98765×9+3=888888





987654×9+2=8888888





9876543×9+1=88888888





98765432×9+0=888888888​