Introduction
The Bar Model Method is the key feature of the well-known Singapore Math which refers to the teaching strategies adopted in the textbooks written by a project
team led by Dr Kho Teck Hong of the Curriculum Development Institute of Singapore in 1980. Since then the bar model method gained international attention
and adoption.
The method involves a procedure of drawing bar models to visualise the concepts of ratios and fractions and to use them in different situations in word problems. The original idea of using line segments instead of bars to solve problems dates back to Euclid in Book V of his monumental work Elements about 2300 years ago. In statistics, bars are effectively used to construct bar charts for representing data and information.
The bar model method is a powerful technique to solve certain types of challenging word problems that appeared in the Singapore Primary School Leaving Examination (PSLE) papers. At the Primary Olympiad level, there are many advanced counting problems which require advanced problem solving skills [5]. The advanced bar model method was developed to solve these problems in [2]. Some well known counting problems such as chicken-rabbit problems,allocation problems and cow grass problems have been dealt with in [3] and [4]. These efforts dispute the argument by some people that the bar model approach is limited only to teaching simple concepts of ratios and fractions and solving word problems at primary level. In this article, we will give some examples to show
how the bar model method can be used in solving challenging counting problems. We begin by mentioning the basic concepts for the bar modelling approach.