Multiply 3-digit numbers having a zero in the tens place
Use this trick to multiply 3-digit numbers having a zero in the tens place in 5 seconds or less.
A 3-digit number is any number that has digits in the ones, tens, and hundreds places. All digits from 100 to 999 are 3-digit numbers.
When the number in the tens place is zero, there is a trick that you can use to perform the multiplication in 5 seconds or less. The very first thing to do is to set up the multiplication vertically. Then, follow the three steps below.
What is 304 times 205?
304
× 205
Step 1
Multiply the numbers in the hundreds place and write the answer on the left.
6
Multiply the numbers in the ones place and write the answer on the right.
6 20
Leave a space between 6 and 20.
6 20
Step 2
Cross multiply as shown in the figure above and add the products.
3 × 5 + 4 × 2 = 23
Step 3
Put 23 between 6 and 20.
304 times 205 = 62320
What is 508 times 406?
508
× 406
Step 1
Multiply the numbers in the hundreds place and write the answer on the left.
20
Multiply the numbers in the ones place and write the answer on the right.
20 48
Leave a space between 20 and 48 numbers.
20 48
Step 2
Cross multiply and add the products.
5 × 6 + 4 × 8 = 30 + 32 = 62
Step 3
Put 62 between 20 and 48.
508 times 406 = 206248