1、97/ 100×99=97/ 100*( 100- 1)=97-97/ 100=9603/ 100
2. 1 3/4× 1/6 ÷ 5/8 = 7/4 * 7/6 * 8/5 = 49/ 15.
3, 3+0/3 ÷ 1.5× 2+0/4 = 10/3 * 2/3 * 9/4 = 5.
4、2.6×99+2.6=(99+ 1)*2.6=260
5、80.7×8.7+8.07× 13=( 12+87)*8.07=807
6、 17/24× 1/5+7/24÷5+ 1/5= 17/24*2/5+ 1/5= 17/60+ 12/60=29/60
7,255 ÷ 255 and 255/256=255*256/255=256
8、3.46× 1.3+3.46×9.7—3.46=3.46*( 1.3+9.7- 1)=34.6
9,0.45× 6 and 1 1/25+3.56÷2 and 2/9 =1449/500+801/500 = 4.5.
10,19.75—(1.75× 8/13+1and 3/4× 5/13) =19.
1 1、 17÷5 1+( 1/68+2/5 1)× 17= 17/5 1+ 1 1/ 12=5/4
12、 1.25×9. 1×0.7+ 1.25×9. 1×0. 1= 1.25*9. 1*0.8=9. 1
13、76×( 1/23— 1/53)+23×( 1/53+ 1/76)—53×( 1/23— 1/76)
= 1- 1+ 1= 1
Second, column calculation. (numerator before "/",denominator after "/")
What is the difference between the sum of (1)3/4 and 2/3 minus them?
3/4+2/3-3/4+2/3=4/3
(2) What is the sum of 3 4/5 and 1/2 plus 1 and 1/4?
19/5+ 1/2+5/4= 19/5+7/4= 1 1 1/20
(3) What is the quotient of 23.5 plus 76.5 and 0.25?
23.5+76.5/0.25=23.5+306=329.5
Third, fill in the appropriate number in ().
6.7×4.8=67×48÷( 100 )
2.25×90=225×(0.9 )
0.65×37.2=372×65÷( 1000 )
4. Two cars, A and B, leave from A and B respectively. The speed of car A is 47 km/h, and the speed of car B is 53 km/h. The two cars meet after 4.5 hours. What's the distance between a and b?
Distance = 4.5 * (53+47) = 4.5 *100 = 450km.