Need help with Gcolle registration

[hannahforesty]

I am at that part where the "math question" is presented. I am unable to figure out/translate it to help me out. Could any one here help me out?
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表示されている数式を計算して、半角数字で答えを入力してください: 必須（半角数字）

ななひクさンは

 

[h4un3bu]

It's a math question, in your case it's 7 - 3 so you have to enter 4

they mix hiragana/katakana on purpose, all you need to know is hiku/tasu - meaning subtract/add.