2.5*32*0. 125=(2.5*4)526 1*(8*0. 125)= 10* 1= 10

3.5-7+6.5=3.5+6.5-7=3

1.2×2.5+0.8×2.5 2.5( 1.2+0.8)=25

8.9× 1.25-0.9× 1.25 = 1.25(8.9-0.9)= 10

12.5×7.4×0.8 = 12.5×0.8×7.4

6.5×9.5+6.5×0.5 =6.5×(4 1029.5+0.5)=65

0.35× 1.6+0.35×3.4 =0.35*( 1.6+3.4)=0.35*5= 1.75

6.72-3.28- 1.72 =6.75-(3.28+ 1.72)=6.75-5= 1.75

0.45+6.37+4.55 =0.45+4.55+6.37=5+6.37= 1 1.37

28× 12.5- 12.5×20=(28-20)* 12.5=8* 12.5= 100

23.65-(3.07+3.65) =23.65-3.65-3.07=20-3.07= 16.93

13.6×4.6+4.6×6.4 0.72×23+77×0.72 2.6×32+32×2.4=( 13.6+6.4)×4.6 =(23+77)×0.72 =(2.6+2.4) ×32=20×6.4 = 100×0.72 =5×32 = 160

( 16534+0.4×0.25)8×7× 1.25=(4+ 1)*7* 10=5*7* 10=350

1.65×99+ 1.65 = 1.65*(99+ 1)= 1.65* 100= 165

27.85-(7.85+3.4)=27.85-7.85+3.4=20+3.4=23.4

48× 1.25+50× 1.25×0.2×8 =7.8*(9.9+0. 1)=7.8* 10=78

4.8×46+4.8×54 =(46+54)*4.8= 100*4.8=480

673-327- 173=673-(327+ 173)=673-500= 173

4.44*2.5= 1. 1 1*(4*2.5)= 1. 1 1* 10= 1 1. 1

3.5÷ 1.4=(3.5÷0.7)÷( 1.4÷0.7)=5÷2=2.5

1+2+3+4+5......+99+ 100=( 1+99)+(2+98)+(3+97)+......+(49+5 1)+50=( 100÷2- 1)* 100+50=4900+50=4950

Extended data:

Mathematics comes from the ancient Greek word μ θ η μ α, which means learning, learning and science. Ancient Greek scholars regarded it as the starting point of philosophy.

In addition, there is a narrow and technical significance. Even in its etymology, its adjective meaning is used to refer to mathematics whenever it is related to learning.

Its plural form in English can be traced back to the neutral plural in Latin and translated from Greek plural by Cicero.

In ancient China, mathematics was called arithmetic, also called arithmetic, and finally it was changed to mathematics. Arithmetic in ancient China was one of the six arts.

Mathematics originated from the early production activities of human beings, and the ancient Babylonians had accumulated some mathematical knowledge, which could be applied to practical problems.

As far as mathematics itself is concerned, their mathematical knowledge is only obtained through observation and experience, and there is no comprehensive conclusion and proof, but their contribution to mathematics should also be fully affirmed.

The knowledge and application of basic mathematics is an indispensable part of individual and group life.