3.5×7分之5+4.5×9分之5
=2.5+2.5
=5
45%÷19分之18—19%
=9/20×19/18-19%
=0.475+0.19
=0.665
2.5—(5分之2×2.5减2分之1)
=2.5-(1-1/2)
=2.5-0.5
=2
8.35×2.4+7.35×7分之2
=20.04+2.1
=22.14
3.5×7分之5+4.5×9分之5
=2.5+2.5
=5
45%÷19分之18—19%
=9/20×19/18-19%
=0.475+0.19
=0.665
2.5—(5分之2×2.5减2分之1)
=2.5-(1-1/2)
=2.5-0.5
=2
8.35×2.4+7.35×7分之2
=20.04+2.1
=22.14