To be successful in algebra, your child absolutely must be able to answer this question correctly. However, in some high schools, fewer than half of students can get the correct answer. The most popular wrong answer by far is 4 – 5 = 1.
There is no way those students can understand algebra. Algebra books are full of endless variations of problems like: Simplify 3x2 + 6x2 + 4 – 5.
The bad news is that subtraction is taught in first and second grades. So middle and high school students who think that 4 – 5 = 1 have been missing a critical element of understanding subtraction for years. The good news is that reversing this misconception about subtraction can be accomplished fairly easily.
However, it is almost never as easy as just telling the student: 4 – 5 does not equal 1 and the correct answer is -1. Or that subtraction is read from left to right. Or that subtraction is not commutative like addition is. These are the standard “fixes” that teachers and parents who notice the student’s problem try. If you are the parent of a child who thinks that 4 – 5 = 1you can see this for yourself by saying one of those standard “fixes.” Then come back to your child in a few weeks with a similar problem, like 2 – 3 = ? or 4 – 6 = ? and see for yourself how effective just telling was.
The good news is that just a few activities and some practice about subtraction will fix this problem forever. Middle and high school teachers aren’t trained to do this, but my Subtraction lessons do accomplish this lifetime understanding.