‏ Exodus 30:13

13Each one who is numbered in the census shall give this: half a shekel
A  shekel was about 2/5 ounce or 11 grams
according to the bshekel of the sanctuary (the cshekel is twenty gerahs),
A  gerah was about 1/50 ounce or 0.6 gram
ehalf a shekel as an offering to the Lord.
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