Question #abbec

Dealing with the multiplication bit first.

#30(30xx30)30#

This is the same as: #30xx30xx30xx30#

Which is also the same as #3xx3xx3xx3xx10xx10xx10xx10#

Which is: #81xx10000=810000#
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Putting it all back together we have

#30+30+810000 = 810060#

This is a classic example of where students will get an incorrect answer because they simply work from left to right, without noticing that there are different operations.

It is VITAL that you identify separate terms FIRST.
(Terms are separated by + and - signs)

Each term will simplify to a single answer and they will be added or subtracted in the last step.

#color(blue)(30)color(red)(+30(30xx30)30)color(forestgreen)(+30)# has 3 terms.

Within each term, the normal order applies. Brackets, then multiply.

#=color(blue)(30)color(red)(+30(900)30)color(forestgreen)(+30)#

#=color(blue)(30)color(red)(+900xx900)color(forestgreen)(+30)#

#=color(blue)(30)color(red)(+810,000)color(forestgreen)(+30)#

#= 810,060#

Notice that the blue and the green terms were already in the simplest form and only the red middle term required simplifying.

In the last step the 3 answers were added.