Problem
Exercise $A$ Copy the problems. Find the products by multiplying the factors in parentheses first. 1) $(3 \cdot 5) 20=3(5 \cdot 20)$ 6) $(25 \cdot 4) 9=25(4 \cdot 9)$ 2) $4(6 \cdot 10)=(4 \cdot 6) 10$ 7) $17(5 \cdot 2)=(17 \cdot 5) 2$ 3) $[5(4 \cdot 13)]=[(5 \cdot 4) 13]$ 8) $[(14 \cdot 10) 2]=[14(10 \cdot 2)]$ 4) $8(2 \cdot 5)=(8 \cdot 2) 5$ 9) $[20(5 \cdot 4)]=[(20 \cdot 5) 4]$ 10) $8(15 \cdot 2)=(8 \cdot 15)^{2}$
Solution
Step 1 ：Calculate the products by multiplying the factors in parentheses first for each equation.
Step 2 ：Compare the left side and right side of the equation to check if they are equal.
Step 3 ：\( \boxed{\text{All the given equations are correct}} \)
