I have a section of floor inside my home that is badly cracked and
slants a couple inches. Hired an Engineer who says the best approach
is cut out the slab and pour a new one. Area is 7x15 (feet), I assume
its 4-6 inches. What's a rough cost in the midwest US to:

a) Cut out and remove old concrete
b) Put in a new portion of the slab.

Thanks !

find out what is required for a footer or foundation beneath this area.
you may be pouring a support footer here. call the nearest cement
company for the cost of a delivered load of various sizes and multiply
by 3 or 4 or more to cover the cost and profit if you were doing just a
sidewalk. if its sold in cubic yards get out that calculator. in your
example you have 7x15x1/2=52.5 cu ft. there are 3x3x3=27 cubic ft per
cubic yard. you're going to need to know what's under the slab and how
not to damage it, plus how to get the heavy concrete to where you need
it. not a do it yourself job. add-on costs of distance from where the
truck will park, extra time for you to delay the delivery of the
concrete while you are playing with the wheelbarrows. did you add on
for the gravel base material and a tamping machine? add on for
delivering it to your basement or wherever this is going.
before you pour, this is a great time to consider that geothermal
heating system you always wanted. or at least replace the driveway,
sidewalks, patio, and the neighbor wants a pad for his shed. check with
your permit office and don't pave the neighbor's property.
how about heated snow melting pipes? do the materials estimate and
dimensions in advance.
call 3 contractors for estimates and send them the information. be
ready for add-ons if they dig and find the rest of the slab has any
hidden problem.