[NOTE: My tutoring is highly individualized.
My multi-strategy problem solving approach leads to best results with fine-tuning to individual student’s weaknesses and strengths.
Among many other things I teach is using observation-reading-based shortcuts.]
Solution 1: (straight consecutive consideration of what is given)
1. Janet grouped 36 stamps into 9 equal groups of 36 / 9 = 4 stamps in each.
2. Adding two stamps to each group will have 4 + 2 = 6 stamps in each group.
3. Having 9 groups with 6 stamps each, Janet will have 9 * 6 = 54 stamps in total.
4. Janet gave away 4 stamps to each her 13 friends, so 4 * 13 = 52 stamps given away.
5. Giving away 52 stamps out of 54 she has, Janet will have left 54 - 52 = 2 stamps.
Answer: Janet will have left 2 stamps.
[Next, is not exactly a different solution, but an observation of the data given allows a shortcut making some step(s) in the "whole" solution unnecessary. Also, some elementary Math students have difficulty with division. While the skills gap should be closed, it's always makes sense to find an approach with simpler calculations.]
Solution 2: (with a shortcut)
1. Adding 2 stamps to each of the 9 groups, Janet will have added 2 * 9 = 18 stamps.
2. Together with original 36 stamps, Janet will have 36 + 18 = 54 stamps.
3. Janet gave away 4 stamps to each of her 13 friends, so 4 * 13 = 52 stamps given away.
4. Giving away 52 stamps out of 54 she has, Janet will have left 54 - 52 = 2 stamps.
Answer: Janet will have left 2 stamps.
[Students like shortcuts. Observing data here allowed to eliminate accounting for grouping of stamps, possibly the most difficult part of the problem to deal with. Kids feel smarter and like my teaching for that, among many reasons.]
