Question

Match the following multiplications with their respective values.

• A. $360$
• B. $384$
• C. $945$

Answer 1

Here, we will be dealing with the multiplication of four numbers.

$\bullet$ $2\times 4\times 6\times 8$
$=(2\times 4)\times 6\times 8$
$=8\times 6\times 8$
$=(8\times 6)\times 8$
$=48\times 8$
$=(40+8)\times 8$

We use the box method to calculate $(40+8)\times 8$.

	$40$	$8$
$8$	$8\times 40$ $=8\times 4\times 10$ $=32\times 10$ $=320$	$8\times 8$ $=64$

$\therefore (40+8)\times 8=320+64=384$

Hence, the value of $2\times 4\times 6\times 8$ is $384$.

$\bullet$ $3\times 4\times 5\times 6$
$=(3\times 4)\times 5\times 6$
$=12\times 5\times 6$
$=(12\times 5)\times 6$
​​​​​​​$=60\times 6$
​​​​​​​$=10\times 6\times 6$
​​​​​​​$=10\times 36$
​​​​​​​$=360$

Hence, the value of $3\times 4\times 5\times 6$ is $360$.

$\bullet$ $3\times 5\times 7\times 9$
$=(3\times 5)\times 7\times 9$
$=15\times 7\times 9$
$=15\times (7\times 9)$
$=15\times 63$
$=(10+5)\times (60+3)$

We use the box method to calculate $(10+5)\times (60+3)$.

	$10$	$5$
$60$	$60\times 10$ $=6\times 10\times 10$ $=6\times 100$ $=600$	$60\times 5$ $=10\times 6\times 5$ $=10\times 30$ $=10\times 10\times 3$ $=100\times 3$ $=300$
$3$	$3\times 10$ $=30$	$3\times 5$ $=15$

$\therefore (10+5)\times (60+3)=600+300+30+15=945$

Hence, the value of $3\times 5\times 7\times 9$ is $945$.