Question

g17a
review up to f 2
grade
mistakes
a
~90%
1
b
~70%
2~4
c
~50%
5~7
d
40%~
8~14
calculate.
(1) $\frac{1}{3} - \frac{5}{9} div 5 =$
(2) $3 - \frac{1}{2} div \frac{1}{5} =$
(3) $3 - 1\frac{3}{4} div \frac{3}{4} =$
(4) $10 - 4\frac{2}{11} \times 1\frac{9}{23} =$
(5) $1 - 1\frac{5}{7} div 3\frac{1}{21} =$
(6) $3 - 3\frac{1}{2} div 1\frac{19}{30} =$
(7) $15 - 5\frac{1}{3} \times 2\frac{1}{4} =$

Explanation:

(1)

Step1: Divide first

$\frac{5}{9} \div 5 = \frac{5}{9} \times \frac{1}{5} = \frac{1}{9}$

Step2: Subtract

$\frac{1}{3} - \frac{1}{9} = \frac{3}{9} - \frac{1}{9} = \frac{2}{9}$

Step1: Divide first

$\frac{1}{2} \div \frac{1}{5} = \frac{1}{2} \times 5 = \frac{5}{2}$

Step2: Subtract

$3 - \frac{5}{2} = \frac{6}{2} - \frac{5}{2} = \frac{1}{2}$

Step1: Convert mixed number

$1\frac{3}{4} = \frac{7}{4}$

Step2: Divide

$\frac{7}{4} \div \frac{3}{4} = \frac{7}{4} \times \frac{4}{3} = \frac{7}{3}$

Step3: Subtract

$3 - \frac{7}{3} = \frac{9}{3} - \frac{7}{3} = \frac{2}{3}$

Answer:

$\frac{2}{9}$

(2)