Assertion: abacus's deck | /r/CapableOf | unregister 1 bead
Facets:
value: to minus 100
type: OTHER
Source sentences:
text: When adding 400 to 6421, it says in column 3 (4 + 4): "Upper deck, register1 bead to add 500; lower deck, unregister 1 bead to minus 100.