換算 and 単位: different numbers for the same quantity
Convert lengths between meters and centimeters, distinguishing a numerical change from a quantity change and checking the conversion basis.
Express a quantity in another unit
換算, read かんさん, means conversion to another unit or basis. 長さをメートルからセンチメートルに換算しました。 reports converting a length from meters to centimeters.
二メートルは二百センチメートルです。 says that two meters equal two hundred centimeters. The numerical notation changes while the length stays equal.
Record the unit with the number
単位, read たんい, is a quantity unit here. 換算した数値には単位も書いてください。 requests writing the unit with the converted value.
Do not decide that two hundred is a longer length than two meters without checking its unit. Align units or confirm the conversion relation before comparing quantities.
The basis needed for conversion
When converting 通貨, identify the currencies and conversion basis. Converting walking distance to 歩数 also requires assumptions such as step length.
Do not apply the two-meter/two-hundred-centimeter relationship to every conversion. Distinguish a fixed unit relation from a context-dependent basis.
Does converting two meters to two hundred centimeters make the length one hundred times greater?
Show the answer and why
No. Different units express the same length. Separate a change in numerical notation from a change in quantity.