1.

4/3-(2/5+3/ 10) 5/7+ 1/4-9/ 14 3/4+3/6-5/8

=40/30-( 12/30+9/30) =20/28+7/28- 18/28 = 18/24+ 12/24 - 15/24

= 19/30 =9/28 =30/24=5/8

5/9+(3/4- 1/2) 1/ 10+3/8-2/5 3/5-(2/ 15+ 1/3)

=20/36+(27/36- 18/36 =4/40+ 15/40- 16/40 = 19/ 15-(2/ 15=5/ 15)

=29/36 =3/40 =2/ 15

2.

1- 1/4-3/8

=8/8-2/8-3/8

= 3/8m

3.

1- 1/5-3/ 10

= 10/ 10-2/ 10-3/ 10

= 1/2

4.

( 1)4/25+ 19/ 100= 16/ 100+ 19/ 100=7/20

(2)7/25+9/50+ 19/ 100=28/ 100+ 18/ 100+ 19/ 100= 13/20

raise a question

(1) How much is the middle and high mountain area more than the low hills?

7/25- 19/ 100=9/ 100

(2) What is the * * * area above 2000m above sea level?

9/50+ 19/ 100=37/ 100

Page 12 1 answer

5.

2/3+3/ 14=3/ 14+2/3

1/2+4/7+3/7= 1/2+(4/7+3/7)

6.

8/9+ 1/9= 1- 1/3=2/3

13/ 18+ 1/9=5/6- 1/3= 1/2

7/ 15+ 1/9=26/45- 1/3= 1 1/45

7.

1/2+ 1/4= 1/4+ 1/2 1/6+ 1/ 10+9/ 10= 1/6+( 1/ 10+9/ 10)

( 1/ 12+ 1/4)+(5/ 12+3/4)=( 1/ 12+5/ 12)+( 1/4+3/4)

8.

1- 1/2= 1/2 1/2- 1/3= 1/6 1/3- 1/4= 1/ 12 1/ 1- 1/5= 1/20

1/2+ 1/6+ 1/ 12+ 1/20

=( 1- 1/2)+( 1/2- 1/3)+( 1/3- 1/4)+( 1/4- 1/5)

= 1- 1/2+ 1/2- 1/3+ 1/3- 1/4+ 1/4- 1/5

= 1- 1/5

=4/5

9.

Graphics 1 2 3 4 5 6 7

The area of the square1/41/41/81/8.

a small part

Figures 7 and 4*** account for:1/8+1/8 =1/4.

Figures 3, 4 and 5*** account for:116+1/8+116 =1/4.

9/50+ 19/ 100=37/ 100