College

Choose one of the examples and discuss it.

Distributive method:
FOIL method:
Expanded notation:

[tex]
\[
\begin{array}{l}
= 1500 + 40 + 71 \times 140 + 5 \\
= 20000 + 2500 + 1000 + 200 + 280 + 35 \\
= 20000 + 2000 + 1000 + 500 + 600 + 200 + 200 + 80 + 30 + 5 \\
= 20000 + 3000 + 1500 + 110 + 5 \\
= 20000 + 3000 + 1000 + 500 + 100 + 10 + 5 \\
= 20000 + 4000 + 600 + 10 + 5 \\
= 24615 \\
\end{array}
\]
[/tex]

1. Multiply the following using both methods.

a. [tex]$578 \times 25$[/tex]

Answer :

Let's solve the problem step by step by multiplying [tex]$578$[/tex] by [tex]$25$[/tex] using two different methods.

--------------------------------------------------
Method 1: Distributive Method

We start by breaking down [tex]$578$[/tex] into parts:
[tex]$$
578 = 500 + 70 + 8.
$$[/tex]
Then, we use the distributive property to get:
[tex]$$
578 \times 25 = (500 + 70 + 8) \times 25 = 500 \times 25 + 70 \times 25 + 8 \times 25.
$$[/tex]

Now, calculate each product:
[tex]\[
\begin{aligned}
500 \times 25 &= 12500, \\
70 \times 25 &= 1750, \\
8 \times 25 &= 200.
\end{aligned}
\][/tex]

Finally, add these results together:
[tex]$$
12500 + 1750 + 200 = 14450.
$$[/tex]

--------------------------------------------------
Method 2: Foble Method

In this method, we break down [tex]$25$[/tex] into two convenient numbers:
[tex]$$
25 = 20 + 5.
$$[/tex]
Then, we rewrite the multiplication as follows:
[tex]$$
578 \times 25 = 578 \times (20 + 5) = 578 \times 20 + 578 \times 5.
$$[/tex]

Now, compute each term:
[tex]\[
\begin{aligned}
578 \times 20 &= 11560, \\
578 \times 5 &= 2890.
\end{aligned}
\][/tex]

Adding these two products gives:
[tex]$$
11560 + 2890 = 14450.
$$[/tex]

--------------------------------------------------
Conclusion

Both methods yield the same result:
[tex]$$
578 \times 25 = 14450.
$$[/tex]

Thus, the final answer is [tex]$\boxed{14450}$[/tex].