Question

Вычислите наиболее простым способом:

1) 751-387-551+387-600

2) (4,7-4,9)+(4,9-5,1)-(-5,1-5,3)

3) 4,6*7,3+5,4*8,5+4,6*8,5+5,4*7,3

4) 9,8*17,42+9,8*5,58-1,8*17,42-1,8*5,58

5) 15,37*7,88-9,37*7,88+15,37*2,12-9,37*2,12

6) 4,54*77,7-4,54*7,7+7,46*77,7-7,46*7,7

7) 75,9*42,3-65,9*42,3+628*1,77-528*1,77

Answer 1

1) 751-387-551+387-600 = (751-551) + (387-387) -600=200-600=-400

 

2) (4,7-4,9)+(4,9-5,1)-(-5,1-5,3) = 4,7-4,9+4,9-5,1+5,1+5,3=(-4,9+4,9)+(5,1-5,1)+(5,3+4,7)=10

 

3) 4,6*7,3+5,4*8,5+4,6*8,5+5,4*7,3 = 7,3*(4,6+5,4)+8,5*(5,4+4,6)=7,3*10+8,5*10=73+85=158

 

4) 9,8*17,42+9,8*5,58-1,8*17,42-1,8*5,58= 9,8*(17,42+5,58)-1,8*(17,42+5,58)=9,8*23-1,8*23=23*(9,8-1,8)=23*8=184

 

5) 15,37*7,88-9,37*7,88+15,37*2,12-9,37*2,12= 15,37*(7,88+2,12)-9,37*(7,88+2,12)=15,37*10-9,37*10=153,7-93,7=60

 

6) 4,54*77,7-4,54*7,7+7,46*77,7-7,46*7,7= 77,7*(4,54+7,46)-7,7*(4,54+7,46)=77,7*12-7,7*12=12*(77,7-7,7)=12*70=840

 

7) 75,9*42,3-65,9*42,3+628*1,77-528*1,77= 42,3*(75,9-65,9)+1,77*(628-528)=42,3*10+1,77*100=423+177=600