Alma 11:11 - 11:15
Alma 11:11 And an amnor of silver was as great as two senums.
An Amnor of silver was equal to two Senums of silver.
Alma 11:12 And an ezrom of silver was as great as four senums.
An Ezrom of silver was equal to four Senums of silver.
Alma 11:13 And an onti was as great as them all.
An Onti was equal to an Ezrom plus a Senums plus a Amnor of silver.
Alma 11:14 Now this is the value of the lesser numbers of their reckoning—
This was the value of each of there silver coins and how they related to each other's value.
Alma 11:15 A shiblon is half of a senum; therefore, a shiblon for half a measure of barley.
Another class of coinage was the Shiblon. It's value was 1/2 a Senum. A Shiblon was equal to 1/2 a measure of barley.
Not sure if this was coinage or using barley like a coin this was what a 1/2 measure of barley would be worth if it was traded straight across to another commodity.