JSFiddle - React, Tailwind, and code Playground
HTML
<form>
Pattern: <input type="text" value="120" pattern="[1][2][1]" title="Summe muss 100 ergeben">
<br />
Readonly: <input type="text" value="120" readonly>
<br />
Pattern+Readonly:<input type="text" value="120" pattern="[1][2][1]" title="Summe muss 100 ergeben" readonly>
<br />
Pattern+Disabled:<input type="text" value="120" pattern="[1][2][1]" title="Summe muss 100 ergeben" disabled>
<input type="submit">
</form>