Hey there! I'm happy to help!
First, we want to see how many Japanese yen there are for 1 U.S. dollar.
This slash (/) means per or for. We see that in the column (USD/1 Unit) the Japanese yen cell has 0.01007. This means that that is how many US dollars there are for each Japanese yen.
However, we want to find how many Japanese yen there are per U.S. dollar. Well, this is the same as writing Yen/1 USD, and in that column we have 99.30487, which means that for every 1 U.S. dollar we have, we have 99.30487 Japanese yen. This means that for $100, we would have 9930.487 Japanese yen.
This / can also represent a dividing sign or a fraction.
What we did is simply take our Units/1 USD and we multiplied the result by $100 (99.30487/1=99.30487, 99.30487×100=9930.487). This matches with the answer 100 USD(99.30487 yen. 1 USD)
Currency exchange is pretty tricky, but if you keep on practicing you'll get very good at it!
Have a wonderful day! :D