{{ $n := .Page.Scratch.Get "gt-assumption-count" }}
{{ $newN := add 1 (int $n) }}
{{ .Page.Scratch.Set "gt-assumption-count" $newN }}
{{ .Page.Scratch.SetInMap "gt-assumptions" (.Get 0) $newN }}
<div class="assumption">
    <span id="gt-assumption-{{ .Get 0 }}" class="assumption-number">
        Assumption {{ $newN }} ({{ .Get 1 }}).
    </span> {{ .Inner }}
</div>