急急急急急！！！数学题三道！！！

Question

1.4/7(7分之4）乘1/9+5/9除以7=？
2. 4/9乘6/11+5/9乘4/11=？
3. 4/9乘12 5/8(12又5分之8)+5 3/8除以2 1/4=？
要过程。
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简便运算

Answer 1

1.4/7×1/9+5/9÷7
=4/7×1/9+5/9×1/7
=4/7×1/9+1/9×5/7
=(4/7+5/7)×1/9
=9/7×1/9
=1/7

2. 4/9×6/11+5/9×4/11
=4/9×6/11+4/9×5/11
=4/9×(6/11+5/11)
=4/9×11/11
=4/9×1
=4/9

3. 4/9×12 5/8+5 3/8÷2 1/4
=4/9×12 5/8+5 3/8÷(9/4)
=4/9×12 5/8+5 3/8×4/9
=4/9×(12 5/8+5 3/8)
=4/9×(12+5+5/8+3/8)
=4/9×18
=8

Answer 2

1,4/63+5/63=9/63=1/7
2,24/99+20/99=44/99=4/9
3,4/9*68/5+23/3*9/4=272/45+207/12=4193/45

Answer 3

(4/7)*(1/9)+(5/9)/7
=4/(7*9)+5/(9*7)
=(4+5)/(9*7)
=9/(9*7)
=1/7

(4/9)*(6/11)+(5/9)*(4/11)
=(4/9)*(6/11)+(5*4)/(9*11)
=(4/9)*(6/11)+(5/11)*(4/9)
=(4/9)*(6/11+5/11)
=4/9

(4/9)*(12 5/8)+(5 3/8)/(2 1/4)
=(4/9)*(12 5/8)+(5 3/8)/(9/4)
=(4/9)*(12 5/8)+(5 3/8)*(4/9)
=(4/9)*(12 5/8+5 3/8)
=(4/9)*18
=8

Answer 4

4/7×1/9+5/9÷7
=1/7×4/9+5/9×1/7
=1/7×（4/9+5/9）
=1/7×1
1/7

4/9×6/11+5/9×4/11
=6/9×4/11+5/9×4/11
=（6/9+5/9）×4/11
=1×4/11
=4/11

4/9×12 5/8+5 3/8÷2 1/4
=4/9×12 5/8+5 3/8÷9/4
=4/9×12 5/8+5 3/8×4/9
=4/9×（12 5/8+5 3/8）
=4/9×18
=8

好好学习，这么简单都不会，你几年级了