try something

src/server.tsx

@@ -62,7 +62,9 @@ function  getRandomQuestion<T>(seed: string, index: number, questions: Question[
 
 function getQuestionPage(question: Question, urls: QuestionURLS, questionIndex: number){
     const source = highlightJs.highlight(question[0].toString(), {language: 'javascript'}).value;
-    return (<div>
+
+    const inputmode = "decimal" ?  Number.isFinite(question[1].answer) : "text";
+        return (<div>
         <div style="text-align:center">
             {questionIndex + 1}/{ questions.length }
         </div>
@@ -77,7 +79,7 @@ function getQuestionPage(question: Question, urls: QuestionURLS, questionIndex:
         <form>
             <div class="field">
                 <div class="control is-expanded">
-                    <input class="input" type="text" placeholder="Answer" name="answer"></input>
+                    <input class="input" type="text" placeholder="Answer" name="answer" inputmode={inputmode}></input>
                     <input type="hidden" name="rendedingTimeStamp" value={Date.now()} ></input>
                 </div>
             </div>