About Stationary

列出算式，把相應的英语数字写在横线上。

Bobby has nine pencils.Sam has eight pencils.How many pencils in all？

There are ten erasers.There are eleven erasers.How many erasers in all？

Dan has six rulers.Lily has seven rulers.How many rulers are there？

Sally buys twelve knives.Joy buys one knife.How many knives do they buy？

I see two pen and five crayons.How many stationaries do I see？