Digital toymaker VTech Holdings Ltd said on Tuesday that data on about 6.4 million children was exposed in a hack of information on customers in more than a dozen countries. The Hong Kong-based firm initially disclosed the attack on Friday, and said hackers took data of nearly 5 million adults, but it did not disclose how many children’s profiles were accessed. In a statement posted on its website on Tuesday, it disclosed that the number of children affected exceeded the number of adults, with data on some 6.4 million children accessed along with data on 4.9 million parents.