Addition and Subtraction on Mac’s Abacus
- Two Examples are given. Each step is shown and explained in detail.
- Example A adds 146 to 365 which has two Carries.
- A Carry is done by trading the 10 Beads of a Row for one Bead in the higher Row.
- Example B adds 5 to 2995 which has three Carries but no other digits to add.
- Again, two Examples are given and explained in detail.
- Example A subtracts 257 from 855 which requires two Borrows.
- A Borrow is done by trading 1 Bead of a Row for 10 Beads in the lower Row.
- Example B subtracts 4 from 5000 which requires three Borrows but no other digits to subtract.