Question

脱式计算，4/5÷[8×(1/2-2/5)]，[1-(1/4+3/8)]÷1/4？

9×13×(5/13+5/9)?

Answer 1

这样计算的：

Answer 2

4/5÷[8×(1/2-2/5)]
=4/5÷（8x1/10）
=4/5÷4/5
=1
[1-(1/4+3/8)]÷1/4
=（1-5/8）x4
=3/8x4
=3/2
9×13×(5/13+5/9)
=9x13x5/13+9x5/9x13
=9x5+5x13
=5x（9+13）
=5x22
=110

Answer 3

4/5÷[8×(1/2-2/5)]
=4/5÷[8×1/10]
=4/5÷4/5
=1
[1-(1/4+3/8)]÷1/4
=[1-5/8]÷1/4
=3/8÷1/4
=3/2
9×13×(5/13+5/9)
=9×13×5/13+9×13×5/9
=45+65
=110