[tauntz]

Anecdotal data from Estonia: I just checked what's the level of maths we have for the 3rd grade (which here corresponds to 9-10 year olds): (Google Translate):

* reads, writes, sorts and compares natural numbers 0–10,000;

* presents a number as the sum of units, tens, hundreds and thousands;

* reads and writes ordinal numbers;

* adds and subtracts numbers mentally within 100, and in writing within 10,000;

* knows the multiplication table (multiplies and divides by single-digit numbers mentally within 100);

* knows the names of the members and results of four arithmetic operations;

* finds the numerical value of a letter in equations by trial and error or by analogy;

* determines the correct order of operations in an expression (parentheses, multiplication/division, addition/subtraction).

So you have elements of pre-algebra but actual algebra will be covered only in the 4th/5th grade (10-12 yo).

[asielen]

Interesting that is 3rd grade at 9-10. 10 year olds in the US are typically in 5th grade. What ages do earlier grades align to?

Generally in the US it is:

* K ~5 yo

* 1st ~6 yo

* 2nd ~7 yo

* 3rd ~8 yo

* 4th ~9 yo

* 5th ~10 yos

Give or take of course since birthdays don't align perfectly.

That seems to roughly align to US standards for the same age but not the same grade.