Teachers: “5×3 is not 3×5”

So, after 6,000 years of scientific progress, now we discover that 5 x 3 is not equal to 3 x 5. That looks like theology, not math: A is not equal to A if you find a good explanation. Good math, teachers! I was perplexed many times looking at my kid’s homework for the same reasons.
As a (high) Math teacher in my country, as both an architect and a professor in other countries, as a professor of other disciplines in three different US states, but perhaps more important, as a struggling father of an elementary school kid, let me tell you something: teachers, your hyper-competitive (competing with Shanghai, right?) new policies and strategies are a receipt for kids (and parents) frustrations. Now I understand why so few young people have some passion about intellectual work.

Why 5+5+5 doesn’t always make 15: Maths exam question divides the internet

A Year 3 pupil was marked down for the solution written out for 5×3

Working out the answer to 5×3 may seem simple enough but the solution one student gave has sparked an online debate.

The maths question, which asks pupils to work out 5×3 using the repeated addition strategy, was posted on Reddit.

It shows a Year 3 pupil being marked down for the solution 5+5+5, with the teacher noting the correct working out should be shown as 3+3+3+3+3.

A second question asks students to draw an array to show and solve 4×6, with the student drawing six rows of four as the answer. This is also marked as incorrect, with the teacher highlighting four rows of six as how it should be written out.

The National Council of Teachers of Mathematics (NCTM) in the US defended how the paper was marked, saying it gives students a better understanding of the problems they are solving.

“Part of what we are trying to teach children is to become problem solvers and thinkers,” said Diane Briars, president of the NCTM.

“We want students to understand what they’re doing, not just get the right answer.”

Can you answer the tricky crocodile maths question, that left students ‘in tears’?

The Common Core State Standards for English and Maths has been widely adopted in the US and outlines what each student should know in each subject by the end of each grade.

Critics claim the different approach can be too confusing for children, while supporters believe the methodology pays dividends when students move on to tackle more difficult problems.

“I would totally argue with the teacher over that for my child,” commented one user.

However another replied: “This is a mark of a good teacher. If your question doesn’t achieve the desired result then the question was the problem, not the answer.”


3 comentarios en “Teachers: “5×3 is not 3×5”

  1. As a person who has a degree in mathematics, I am appalled at the teacher grading those two answers as wrong. I agree that it demonstrates defective math teaching. Since most year 3 teachers are not required to have a degree in mathematics, it is possible and highly probable in the United States for someone to get an elementary school teaching credential without understanding the basic concepts of algebra. It does not surprise me that this teacher made grading mistakes nor that the elementary education community supported the teacher’s mistakes rather than the fact that the child’s answers were correct and demonstrated a basic principle of algebra. This shows that common core teaching is flawed.

    It also explains why students in so many other countries score higher in mathematics than students in the US. My own child’s experience from 20 years ago is that even middle school teachers in the US teaching algebra are allowed to teach algebra without a bachelor’s degree in mathematics in addition to their teaching credential. This was not true 50 years ago. The standards for teaching have been greatly lowered from 50 years ago. The salaries for teachers in many states in the US are terrible and have also gone downhill since 50 years ago.

    Lastly I am appalled that freshmen at some University of California campuses are allowed to take remedial English and remedial Math classes. These classes should not be offered at UC campuses and freshmen requiring them should never have been granted admission to any UC campus.

    C. Mello


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