we know that
One very simple form of estimation is rounding.
To round off whole numbers:
Find the place value you want (the "rounding digit") and look to the digit just to the right of it.
If that digit is less than [tex] 5 [/tex], do not change the "rounding digit" but change all digits to the right of the "rounding digit" to zero.
If that digit is greater than or equal to [tex] 5 [/tex], add one to the rounding digit and change all digits to the right of the rounding digit to zero.
Part a) Estimate[tex] (368+231) [/tex] rounding the numbers to nearest hundreds
[tex] 368 [/tex]
[tex] 368 > 350 [/tex] ------> round up to [tex] 400 [/tex]
[tex] 231 [/tex]
[tex] 231 < 250 [/tex] ------> round down to [tex] 200 [/tex]
so
[tex] (368+231)=400+200=600 [/tex]
therefore
the answer part a) is
[tex] 600 [/tex]
Part b) Estimate [tex] (368+231) [/tex] rounding the numbers to nearest tens
[tex] 368 [/tex]
[tex] 68 > 65 [/tex] ------> round up to [tex] 370 [/tex]
[tex] 231 [/tex]
[tex] 31 < 35 [/tex] ------> round down to [tex] 230 [/tex]
so
[tex] (368+231)=370+230=600 [/tex]
therefore
the answer part b) is
[tex] 600 [/tex]
