If it hasn't happened already, your kids will one day ask why notebooks, pencils and rulers were ever used in the classroom. As of now, there are about 13.2 million computing devices in primary and secondary schools in the U.S., according to Education Market Research, which conducted a survey last spring. The survey puts the number of desktops at 4.7 million, laptops at 3.9 million and 2.3 million tablets. Meanwhile, there are estimated one million Chromebooks in grades K-12. In other developments, EMR predicts that tablet spending is on pace to increase by 8.6 percent during the upcoming school year.