Reading a source in kuzushiji 1 – solution

Solution: に２　つ３.

Explanation: The hiragana に appears twice in the second line, once as a simplification of the kanji 仁 (currently used as the standard hiragana for the syllable ’ni’), and the second time as a simplification of the kanji 尓(a kanji whose usage for representing this hiragana has been lost in time). The hiragana つ  also appears twice in the third line, the first as a derivation of the kanji 川 (currently used as the standard hiragana for the syllable ’tsu’), and then second as a simplification of the kanji 徒.