Q: Does "In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money." provide a valid answer to "A checkered cloth on a table was used in medieval Europe to help count what?"?
A: yes

Q: Does "Ports were easier to find and made better targets." provide a valid answer to "Why were ports better targets?"?
A: yes

Q: Does "Before the 20th century, the term matter included ordinary matter composed of atoms and excluded other energy phenomena such as light or sound." provide a valid answer to "In what century was the term matter defined excluding energy phenomena like light and sound?"?
A: yes

Q: Does "Some scholars[who?] suggest any labour by children aged 18 years or less is wrong since this encourages illiteracy, inhumane work and lower investment in human capital." provide a valid answer to "What happens to the wages of adults?"?
A:
no