Cada problema debe tener un proceso de cálculo necesario. ① 23× 2424-24× 2323 ② 52,44× 79,45+159× 47,56+79,55× 52,44 ③ 18× 3.

①23×2424-24×2323

=23×24×101-24×23×101

=0;

②52,44×79,45+159 ×47,56+79,55×52,44

=52,44×(79,45+79,55)+159×47,56

=52,44×159+159×47,56

=159× (52,44+47,56)

=159×100

=15900;

③ 18× 3 7 +0,65× 8 13 - 2 7 ×18+ 5 13 ÷1 7 13

= 54 7 + 2 5 - 32 7 + 1 4

=( 54 7 - 32 7 )+( 2 5 + 1 4 )

=3 1 7 + 13 20

=3 111 140;

④ 2,75+ 5 12 -1,4+2 1 4 ÷ 5 12 -87,5%

=2,75+ 5 12 -1,4+5,4-87,5%

=3 1 6 -1,4+5,4-87,5%

=3 1 6 +4-87,5%

=6 7 24;

⑤ 2010×2008+1 2009 + 2009+2010×2008 2009×2010-1

= 2009×2008+2008 +1 2009 + 2009+2008×2009+2008 2009×(2009+1)-1

= 2009×(2008+1) 2009 + 2009×(2008+1)+2008 2009×2009+ 2008

=2009+1

=2010.