PLS HELP

Please

What are “like terms”? why can we only add like terms?

On average, how many more hits will he get when he bats 100 times at home during the day as opposed to 100 times away at night?

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.