You should be able to read the dates on the Mexican coins just fine. They
use western numerals and the same calendar. Their denominations are
occasionally in Spanish, but take advantage of that as a learning
opportunity!
The Japanese coins will present two problems:
1) They use Japanese characters instead of the numerals we are used to.
There are decoder charts in most any book that covers world coins.
2) They date their coins according to the regnal year of the emperor. Thus
Yr. 1 of emperor Hirohito = C.E. 1926, and Yr. 1 of the current emperor
Akihito = C.E. 1989.
Any Japanese coins you are likely to encounter will have only two digits in
the date because of this.
Any more questions, feel free to ask. Even though we occasionally drift off
topic around here, coins are still the main reason most of hang out in rcc.
James the Chronologist
I see that you also asked about Chinese coins.
If they are PRC, they will likely have western dates in western numerals.
If not, the more recent ones still may have western dates in western
numerals.
If they are Republic of China coins, they will have dates from the founding
of the republic (Yr. 1 = C.E. 1912) in Chinese characters. Again, any good
world coin catalog should have a decoder chart.
James