1 125-997 998+ 1246+9989 (8700+870+87)÷87

125×8.8 1.3+4.25+3.7+3.75 17. 15-(3.5-2.85)

3.4×99+3.4 4.8× 1.0 1 0.4×(2.5÷73)

( 1.6+ 1.6+ 1.6+ 1.6)×25 ( + - )÷

12.3-2.45-5.7-4.55 2 + 0. 125×0.25×64

64.2×87+0.642× 1300 78×36+7.8×74 1-7 17+ 8

0. 125× +0.5 2.42 +4.58 -43

25÷ 100 4.25-3 -(2 - 1 )

( 1) 1.25* 17.6+36. 1/0.8+2.36* 12.5

1.25* 17.6+36. 1/0.8+2.36* 12.5

=(5/4)* 17.6+36. 1*(5/4)+23.6*(50/4)

= 176/8+36 1/8+236/8

=773/8=96.625

(2)7.5*2.3+ 1.9*2.5

7.5*2.3+ 1.9*2.5

=7.5*( 1.9+0.4)+ 1.9*2.5

=(7.5+2.5)* 1.9+7.5*0.4

= 19+3 =22

(3)2004/2003*2005

2004/2003*2005

=(2004/2003)*(2003+2)

=2004+4008/2003

(4)276*543-267/276+543*275

276*543-267/276+543*275

=543*(276+275)-267/276

=543*55 1-267/276

(5) 17/5 1+ (68/ 1+5 1/2)* 17

17/5 1+ (68/ 1+5 1/2)* 17

I can't do the following. There seems to be some simple methods. I wonder if you copied the title wrong. Is 68 in your 68/ 1 a numerator or a denominator? The denominator should be correct.

(6)(3.25-0.8*8/5)/(6 4/ 1-3.5)

Is it 6 65438+4 0? It should be 6 1/4 1.

1) 52 and 251× 79.45+159× 47.56+79 and 251× 52.44

=52.44×79.45+ 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)2002+200 1-2000- 1999+ 1998+ 1997- 1996- 1995+……+2+ 1

=(2002-2000)+(200 1- 1999)+( 1998- 1996)+( 1997- 1995)+……+(6-4)+(5-3)+2+ 1

= 2+2+2+2+...+2+2 (from 3-2002 * * 2000, with 1000 binary) +2+ 1.

= 1000×2+2+ 1

=2003

Questions 4 and 5 both use a conversion formula1/(a× b) =1/(b-a )× (1/a-1/b).

Such as115 =1(3× 5) =1(5-3 )× (1/3-1/5) =/kloc-0.

4)( 1×2) +(2×3) +(3×4)+...+( 10× 1 1)

= 1/( 1×2)+ 1/(2×3)+ 1/(3×4)+……+ 1/( 10× 1 1)

=( 1- 1/2)+( 1/2 - 1/3)+( 1/3 - 1/4)+……+( 1/ 10 - 1/ 1 1)

= 1- 1/ 1 1

= 10/ 1 1

5) One third+one fifteenth+one thirty-fifth+one sixty-third+one ninety-ninth.

= 1/( 1×3)+ 1/(3×5)+ 1/(5×7)+ 1/(7×9)+ 1/(9× 1 1)

= 1/2×( 1- 1/3)+ 1/2×( 1/3- 1/5)+ 1/2×( 1/5- 1/7)+ 1/2×( 1/7- 1/9) + 1/2×( 1/9- 1/ 1 1)

= 1/2×( 1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/ 1 1)

= 1/2×( 1- 1/ 1 1)

= 1/2× 10/ 1 1

=5/ 1 1

6) One sixth and seven fifths+twelve nineties and twenty+eleven thirty-thirteen forty-two+fifteen fifty-six.

(According to the prompt, 1 and 1/2 = 1+ 1/2,+1/3 = 5/6 ...)

=( 1+ 1/2)-( 1/2+ 1/3)+( 1/3+ 1/4)-( 1/4+ 1/5)+( 1/5+ 1/6)-( 1/6+ 1/7)+( 1/7+ 1/8)

= 1+ 1/2 - 1/2 - 1/3 + 1/3 + 1/4 - 1/4 - 1/5 + 1/5 + 1/6 - 1/6 - 1/7 + 1/7 + 1/8

= 1+ 1/8

=9/8