## Commutative Law: 100.21 + 23.42 + 2.79 - 13.40

Simplificatation, evaluation, linear equations, linear graphs, linear inequalities, basic word problems, etc.

### Commutative Law: 100.21 + 23.42 + 2.79 - 13.40

Just bought a home tutorial and the very firsr lesson speaks about commutative law which is confusing me.
Sample question was
100.21 + 23.42 + 2.79 - 13.40 =
using BEDMAS rule - we worked through the problem and came up with the answer 113.02
which the tutorial said was wrong.
The tutorial says we should add 100.21 + 2.79 (103) then subtract 23.42 - 13.40 (10.02) for an answer of 92.98 (based on this "commutative law"
what the heck???? is the tutorial correct? if so, can someone explain the concept to this confused middle-aged mom???
thanks
bonnie

Posts: 1
Joined: Wed Feb 04, 2009 6:33 pm

### Re: Commutative Law

bonnie wrote:Just bought a home tutorial and the very firsr lesson speaks about commutative law which is confusing me.

Hi Bonnie, I hope you didn't spend too much on it, judging by its answer!

Sample question was
100.21 + 23.42 + 2.79 - 13.40 =
using BEDMAS rule - we worked through the problem and came up with the answer 113.02
which the tutorial said was wrong.

If the question really was as displayed above, then 113.02 is correct.

The tutorial says we should add 100.21 + 2.79 (103) then subtract 23.42 - 13.40 (10.02) for an answer of 92.98 (based on this "commutative law"
what the heck???? is the tutorial correct? if so, can someone explain the concept to this confused middle-aged mom???
thanks

Judging by their answer, maybe there was a typo in the question.

Perhaps it should have been: 100.21 - 23.42 + 2.79 + 13.40

DAiv
DAiv

Posts: 44
Joined: Tue Dec 16, 2008 7:47 pm