Janice thinks that 20 hundredths is equivalent to 2 thousandths because 20 hundreds is equal to 2 thousands. use words and a place value chart to correct janice's error

Hundred is The expression for hundred in the decimal system is 100. 
20 hundreds stands for 20*100=2000
Hundredths on the other hand is the second place after the decimal.
20 hundredths stands for 0.02.
So, it is true that 20 hundreds (20*100=2000) is equal to 2 thousands (2*1000=2000), 2000=2000, but is not true that 20 hundredths (0.02) is equivalent to 2 thousandths (2*1000=2000). 

The shelves will hold 270 books in total