Question

1 add parentheses to make true.
$3×(5 + 4)-8 = 19$
$(4 + 9)×2 - 5 = 21$
2 solve.
$1\frac{3}{7}\div\frac{1}{2}=\frac{10}{7}×(\frac{2}{1})=\frac{20}{7}=2\frac{6}{7}$
3 what is the area?
(there is a rectangle with length 8.1 m and width 5.6 m, and a triangle with base 12.4 in and height 7.25 in)
4 solve
$4\frac{1}{3}=\frac{□}{□}$ $3\frac{5}{8}=\frac{□}{□}$
$\

$$\begin{array}{r}1\\frac{3}{7}=\\frac{□}{□}\\\\ + \\\\ \\hline\\end{array}$$

$ $\

$$\begin{array}{r}1\\frac{1}{3}=\\frac{□}{□}\\\\ - \\\\ \\hline\\end{array}$$

$
5 order from greatest to least.
-79, -71, 70, -74, -7 →
-61, -60, -32, -67, -70 →

Explanation:

Step1: Verify first parenthesis equation

$3 \times (5 + 4) - 8 = 3 \times 9 - 8 = 27 - 8 = 19$

Step2: Verify second parenthesis equation

$(4 + 9) \times 2 - 5 = 13 \times 2 - 5 = 26 - 5 = 21$

Step3: Calculate rectangle area

Area = length $\times$ width = $8.1 \times 5.6 = 45.36$

Step4: Calculate triangle area

Area = $\frac{1}{2} \times$ base $\times$ height = $\frac{1}{2} \times 12.4 \times 7.25 = 44.95$

Step5: Convert mixed number to improper fraction

$4\frac{1}{3} = \frac{4 \times 3 + 1}{3} = \frac{13}{3}$

Step6: Convert mixed number to improper fraction

$3\frac{5}{8} = \frac{3 \times 8 + 5}{8} = \frac{29}{8}$

Step7: Add mixed numbers (convert first)

$1\frac{3}{7} = \frac{10}{7}$, so $\frac{10}{7} + \frac{10}{7} = \frac{20}{7}$

Step8: Subtract mixed numbers (convert first)

$3\frac{5}{8} = \frac{29}{8}$, $1\frac{1}{3} = \frac{4}{3}$; $\frac{29}{8} - \frac{4}{3} = \frac{87 - 32}{24} = \frac{55}{24}$

Step9: Order first number set

Positive > negative; larger negatives are smaller: $70, -7, -71, -74, -79$

Step10: Order second number set

Larger negatives are smaller: $-32, -60, -61, -67, -70$

Answer:

1. $3 \times (5 + 4) - 8 = 19$ (valid); $(4 + 9) \times 2 - 5 = 21$ (valid)
2. $1\frac{3}{7} \div \frac{1}{2} = \frac{10}{7} \times \frac{2}{1} = \frac{20}{7} = 2\frac{6}{7}$ (valid)
3. Rectangle area: $45.36$ m²; Triangle area: $44.95$ in²
4. $4\frac{1}{3} = \frac{13}{3}$; $3\frac{5}{8} = \frac{29}{8}$; $1\frac{3}{7} + 1\frac{3}{7} = \frac{20}{7}$; $3\frac{5}{8} - 1\frac{1}{3} = \frac{55}{24}$
5. First set: $70, -7, -71, -74, -79$; Second set: $-32, -60, -61, -67, -70$