fix(curriculum): clean-up Project Euler 261-280 (#42905)

* fix: clean-up Project Euler 261-280

* fix: typo

* fix: typo

* fix: typo

curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-273-sum-of-squares.md

@@ -8,16 +8,24 @@ dashedName: problem-273-sum-of-squares
 
 # --description--
 
-Consider equations of the form: a2 + b2 = N, 0 ≤ a ≤ b, a, b and N integer.
+Consider equations of the form: $a^2 + b^2 = N$, $0 ≤ a ≤ b$, $a$, $b$ and $N$ integer.
 
-For N=65 there are two solutions: a=1, b=8 and a=4, b=7. We call S(N) the sum of the values of a of all solutions of a2 + b2 = N, 0 ≤ a ≤ b, a, b and N integer. Thus S(65) = 1 + 4 = 5. Find ∑S(N), for all squarefree N only divisible by primes of the form 4k+1 with 4k+1 < 150.
+For $N = 65$ there are two solutions:
+
+$a = 1, b = 8$ and $a = 4, b = 7$.
+
+We call $S(N)$ the sum of the values of $a$ of all solutions of $a^2 + b^2 = N$, $0 ≤ a ≤ b$, $a$, $b$ and $N$ integer.
+
+Thus $S(65) = 1 + 4 = 5$.
+
+Find $\sum S(N)$, for all squarefree $N$ only divisible by primes of the form $4k + 1$ with $4k + 1 < 150$.
 
 # --hints--
 
-`euler273()` should return 2032447591196869000.
+`sumOfSquares()` should return `2032447591196869000`.
 
 ```js
-assert.strictEqual(euler273(), 2032447591196869000);
+assert.strictEqual(sumOfSquares(), 2032447591196869000);
 ```
 
 # --seed--
@@ -25,12 +33,12 @@ assert.strictEqual(euler273(), 2032447591196869000);
 ## --seed-contents--
 
 ```js
-function euler273() {
+function sumOfSquares() {
 
   return true;
 }
 
-euler273();
+sumOfSquares();
 ```
 
 # --solutions--