The exchange rate of the dinar changes little, if at all, against the US dollar, unless the government of Jordan decides to revalue or devalue. The rate has been JD .708 per US$1.00 (JD 1.000 = US$1.412) for some time.
For units smaller than a dinar you will hear the words:
-fils - there are 1,000 fils in a dinar
-piastre - there are 100 piastres in a dinar - a piastre is 10 fils
-qirsh - equal to a piastre
The government is in the process of phasing out fil coinage. Older coins say fils, newer coins of the same size say the equivalent number of piastres. The older fils coins do not have numerals on them.
The value is written in English script but can be very difficult to read. Learn the sizes. The newer piastre or qirsh coins do have Arabic numerals (that is the number as written by Arabs), plus the value spelled out in English.
This will help you learn the Arabic numerals for 1, 5 and 0. Coins come in 1 dinar, 1/2 dinar, 1/4 dinar, 100 fils (10 piasters), 50 fils (5 piasters), 25 fils (2.5 piasters), and 10 fils (1 piaster).
Paper money comes in 1/2, 1, 5, 10 and 20 dinar denominations. They vary in size and color, but it is possible to mix up the 1 and 10 if you are not careful.