jencam wrote:

I'm not sure when primary schools introduced algebra into the curriculum but it was certainly there when my son was in KS2 during the late 1990s.

It was probably introduced formally when the primary NC came into operation. I never touched algebra at primary school. The maths course was heavily biased towards calculations involving integers and money and the school operated a strict no calculators policy. I found numerical calculations like how to multiply two 4 figure numbers tedious so took more interest in real maths - like algebra. Several other people have told me they were taught algebra in primary school back in the 1980s so some schools must have been teaching it before the NC.

Napier wrote:

I find it incredulous that any primary school teacher could make such a mistake as this even if maths isn't their strong subject. My primary school taught about operator priority when mixed calculations were first encountered.

I reckon it was quite common for primary schools to erroneously teach mixed calculations from left to right rather than by BIDMAS. I discussed BIDMAS vs calculating from left to right a few years ago on

another AS forum and a few other people admitted to being taught to calculate from left to right.

"A Complete O Level Mathematics" by A Greer, that was published in 1976, was the book I used to learn algebra, calculus, and trigonometry whilst at primary school. On the first page of Chapter 1 the sequence of operations is described but the word BIDMAS isn't mentioned. It states:

5 x 8 + 7 = 40 + 7 = 47 (not 5 x 15)

8 / 4 + 9 = 2 + 9 = 11 (not 8 / 13)

5 x 4 - 12 / 3 + 7 = 20 - 4 + 7 = 23

Which demonstrates the priority of operations.