I. From 5th grade Math Trailblazers Student Guide, Unit 9, lesson 6: Calculator Strategies: Addition and Subtraction of Fractions, final problem set (p. 321) [click to enlarge]:
II. From the 5th grade Singapore Math, Primary Mathematics 5B, Fractions chapter, about half-way through (pp. 58-59) [click to enlarge]:
III. Extra Credit:
What are Singapore Math students missing out on by never receiving direct instruction in "calculator strategies"?
When it comes to calculator strategies, which is better: direct instruction, or child-centered discovery?