Adding Strategies 7,8,9,10 : These skills are on the Grade 3 curriculum, but they may be used at any level. For instance, looking for the gap between the given numbers and a self-determined "centre" is the concept of absolute value on the Grade 10 curriclum. The horizontal format here is for those older grades.
Answers are given in the format of the questions so that the student will see all the work that's needed and where he might have gone wrong.
The skills of making pictures as well as writing the math are useful for exercising the whole brain. Sometimes the picture will trigger the correct calculation. Many people have trouble visualizing math concepts.