Complete PDF interactive worksheets online, with no printing! Learning to add quickly with K12XL drills for vertical addition worksheet including 1 or 2 digit addition problems or even mixed digit ones for one single page. Boost the abilities of your students by helping them to learn all single digit addition problems by heart and get them race be able to solve all 100 addition problems within 5 minutes being the star of addition! This worksheet randomly creates impressively large number of quick tasks of 20, 60 or even 100 quick addition problems for 1, 3 or 5 minutes to be solved. To make the addition even more interesting, you can select the range for the 2 addends separately.