Arithmetic of Computers

Well, let’s see:

	RULE

8 + ( − 6) = 2	To add numbers of unlike sign, find the difference of the absolute values, attach the sign of the number with the larger absolute value.

15 − 19	To subtract any number, change the sign of the number being subtracted; then add instead, following the rule, in this case, for addition of unlike signs.
= 15 − ( + 19) = sign changed ↓ 15 + ( − 19) = − 4 ↑ add instead

− 5 − ( − 8)	See subtraction rule above.
= sign changed ↓ − 5 + ( + 8) = 3 ↑ add instead

− 2 + 5	See rule above for addition of numbers of unlike sign.
= − 2 + ( + 5) = 3

They’re all correct. Return to Page 93 and try again.