More on simple arithmetic skills that people don’t always understand as well as they think they do, leading to difficulties at a later stage.<\/p>\n
In the OU Science Faculty we use the mnemonic BEDMAS (others use BODMAS or BIDMAS) to remind students of the\u00a0\u00a0rules governing the order of precedence for arithmetic operations:<\/p>\n
B<\/strong>rackets take precedence over<\/p>\n E<\/strong>xponents. Then<\/p>\n D<\/strong>ivision and<\/p>\n M<\/strong>ultiplication must be done before<\/p>\n A<\/strong>ddition and<\/p>\n S<\/strong>ubtraction.<\/p>\n When analysing student responses to iCMA questions, lack of understanding of the rules of precedence and related issues, whilst not contributing to as many errors as do problems with fractions and\/or units, it’s still up there as a common difficulty. Sometimes the problem\u00a0can be attributed\u00a0to poor calculator use e.g.\u00a0a lot of students interpret\u00a03\u00a06\/3 <\/sup>as meaning (3\u00a06<\/sup>)\/3,\u00a0 perhaps because they don’t stop and think before using their\u00a0calculator. \u00a0This misunderstanding (seen in lots of variants of a question in summative use) led to a talk I used to give: ‘Why is the answer always 243?’. \u00a0But it goes deeper than that! For example, even after teaching students how to multiply out brackets etc., many think that\u00a0(x + y)\u00a02 <\/sup>is the same as\u00a0\u00a0x2<\/sup>+ y2<\/sup>. Mistakes of this ilk are completely understandable, but it is nevertheless something to watch out for.<\/p>\n","protected":false},"excerpt":{"rendered":" More on simple arithmetic skills that people don’t always understand as well as they think they do, leading to difficulties at a later stage. In the OU Science Faculty we use the mnemonic BEDMAS (others use BODMAS or BIDMAS) to … Continue reading