JSFiddle - React, Tailwind, and code Playground
JavaScript
var gridString = "73167176531330624919225119674426574742355349194934<br>\
96983520312774506326239578318016984801869478851843<br>\
85861560789112949495459501737958331952853208805511<br>\
12540698747158523863050715693290963295227443043557<br>\
66896648950445244523161731856403098711121722383113<br>\
62229893423380308135336276614282806444486645238749<br>\
30358907296290491560440772390713810515859307960866<br>\
70172427121883998797908792274921901699720888093776<br>\
65727333001053367881220235421809751254540594752243<br>\
52584907711670556013604839586446706324415722155397<br>\
53697817977846174064955149290862569321978468622482<br>\
83972241375657056057490261407972968652414535100474<br>\
82166370484403199890008895243450658541227588666881<br>\
16427171479924442928230863465674813919123162824586<br>\
17866458359124566529476545682848912883142607690042<br>\
24219022671055626321111109370544217506941658960408<br>\
07198403850962455444362981230987879927244284909188<br>\
84580156166097919133875499200524063689912560717606<br>\
05886116467109405077541002256983155200055935729725<br>\
71636269561882670428252483600823257530420752963450";
//This will work for any four numbers on the same line, but not if they are on different lines
var toReplace = "8617";
document.write(gridString.replace(toReplace, "<strong>" + toReplace + "</strong>"))