Chart reading versus estimation: large numbers in Investigations vs. Singapore Math.
I. An early problem set involving large numbers in the 5th grade TERC/Investigations Student Activity Book, from Unit 3 of the book [click to enlarge]:
II. A continuation of the first first problem set involving addition and subtraction (and multiplication and division) of multiples of ten from large numbers in the 5th grade Singapore Math Primary Mathematics 5A Workbook, from Unit 1 of the book [click to enlarge]:
III. Extra Credit:Is chart reading a 21st century skill?