Surprise about my mother - 意外な面

My sister started to work for simple arithmetic, Japanese reading and writing Chinese characters with my mother. These are again all for brain functioning. However, my mother would not be happy to know the purpose of doing the exercise. My sister asked her to read out the Japanese so that she can practice word-processing on the computer. Of course, my mother is happy to help my sister. The cooperative work started smoothly. We, daughters were surprised by our mother's ability to do arithmetic and to write Chinese characters. We learned a new aspect of our mother. Our mother seems to enjoy doing these as well daily with her one of daughters.

妹が頭のドリルを母にさせ始めた。算数と国語の読み書きである。もちろん、これが母親のボケ退治のためだと知ったら母も嫌がる。妹が母にパソコンの練習をするから読み上げてと頼んで始めたらしい。娘の為なら喜んでしてくれる。やっていくうちに我々は母の意外な面を発見。なかなかやるではないか。算数も漢字書きも。母自身も娘と毎日するのが楽しみなようだ。