Calculator = 105 yen ($1.12 €0.87)

My son wanted to have a calculator and we went to a 100 yen shop to buy it. 

It cost 105 yen ($1.12 €0.87). It is run by a battery. An expensive calculator has a solar battery, but unfortunately we can not afford a such calculator in 100 yen shop (occasionally you can). 

We used to use abacuses or slide rules 40 years ago. Many kids including myself, went to abacus school at that time. However those manual devices were faded out from the mainstream. Some kids still go to abacus school to improve their ability of mental calculation.

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Abacus