Question

Which equations show that the set of whole numbers is not closed under subtraction?

Choose all answers that are correct.

A.
1 – (–2) = 3

B.
1 – 2 = –1

C.
2 – 0 = 2

D.
2 – 4 = –2

Answer 1

The set of whole numbers is defined to be

W = {0, 1, 2, 3, 4, 5, ...}

basically the set with 0 and every positive integer

Answer 2

a and c

Answer 3

@jim_thompson5910

Answer 4

notice how with A, they took the numbers 1 and -2 and subtracted

but there's a problem: -2 is NOT part of the whole number set I defined above

Answer 5

bcd @jim_thompson5910

Answer 6

Reread the initial question:

Which equations show that the set of whole numbers is NOT closed under subtraction?

Answer 7

some examples do show closure, others do not

Answer 8

so just c

Answer 9

@jim_thompson5910

Answer 10

2 – 0 = 2 is actually an example showing closure

they want something that does NOT show closure

Answer 11

they want something that shows

(WHOLE NUMBER) - (WHOLE NUMBER) = (NON WHOLE NUMBER)