Author here. This is helpful feedback, we could have perhaps taken more time before jumping in on the Modern Bagelry example. A common misconception is that one account needs to increase while the other needs to decrease. But what we are actually showing that they can both increase or decrease in tandem, depending on the debit and credit entries in the transaction and the direction of the accounts. In the first transaction cash increases because it's a debit entry in a debit normal account (cash); and equity also increases because it's a credit entry in a credit normal account (equity).