Question

800+j+6200-10-7000=90
(Metoda mersului invers)

Answer 1

90+7000=800+j+6200-10    90+7000-800+10-6200=j          j=100

Answer 2

800+j+6200-10-7000=90 |+7000
800+j+6200-10=7090 |+10
800+j+6200=7100 |-6200
800+j=900 |-800
j=100

VERIFICARE: 800+100+6200-10-7000=90
900+6200-10-7000=90
7100-10-7000=90
7090-7000=90
90=90 (Adevărat)

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