How difficult are the problems that kids can solve with Singapore Maths?

Here’s an excerpt from a great article on Singapore Math from Education Leadership, a top journal from teaching and learning exerpts in K-12 education (download full article here).

Here is a math problem you can solve easily:

A man sold 230 balloons at a fun fair in the morning. He sold another 86 balloons in the evening. How many balloons did he sell in all?

And here is one you can’t:

Lauren spent 20 percent of her money on a dress. She spent 2/5 of the remainder on a book. She had $72 left. How much money did she have at first?

In Singapore, where 4th and 8th grade students consistently come in first on international math exams, students learn how to solve both problems using the same bar model technique. Students first encounter the technique in 3rd grade, where they apply it to very simple problems like the first one. In grades 4 and 5, they apply the same versatile technique to more difficult, multistep problems. By grade 6, they are ready to solve really hard problems like the second one.

The Mathemagis program follows the same approach and teaches the bar-model method as early as Grade 2.  Students progress to more complex 2 or 3 step word problems in the 3rd grade and do at least 4 to 6 steps by the time they are in Grade 5.  Grade 5 word problems are equivalent to first year high school problems solved in traditional algebra classes. The bar-model allows the students to solve more complex math problems that requires algebra in the traditional curriculum. The foundation of analysis and visualization is laid in the primary grades and eases the transition to high school.