How to specific letter spacing in a sentence

I have added letter-spacing:-1px. However I also need to letter-spacing the hiragana(japanese) numbers. I can't solve this problem by using romanji letter. How do I tighter(make less space) only for these number?

I tried to add <span style>between the sentence, but it did not do anything.

See my jsfiddle

<div style="letter-spacing: -１px; font-weight: 500; text-transform: lowercase;"><strong>８４m<sup>2</sup> ~ ４５０m<sup>2</sup> 食事食事室</strong></div>

Solution

you can use span for that, and avoid using inline styles:

Snippet

div {
  letter-spacing: -1px;
}
.has-letter-spacing{
  letter-spacing: -5px;
}

<h3>HAS LETTER-SPACING IN SPAN</h3>
<div>
  <strong>８４m<sup>2</sup> ~ ４５０m<sup>2</sup> <span class="has-letter-spacing">食事食事室</span></strong>
</div>
<hr />
<h3>NO LETTER-SPACING IN SPAN</h3>
<div>
  <strong>８４m<sup>2</sup> ~ ４５０m<sup>2</sup> <span>食事食事室</span></strong>
</div>