Answer: ummm
Step-by-step explanation:
So the number of pencils bought can be represented by an equation:

, where n is the number of notebooks bought. Since Helen bought 5 notebooks, simply plug 5 into n:

. So Helen bought 12 pencils.
If you use a textbook for this i would recommend slader, it really works!!
Answer:
240
Step-by-step explanation:
4 x 2 x 3 = 24 x 10 = 240 milimeters
Hey there! I'm happy to help!
There are 1,000 millimetres in 1 meter. So, we multiply by 1,000.
872(1000)=872,000
There are 872,000 mm in 872 m.
Have a wonderful day! :D