Decimal Multiplication

  • 2 months ago
Transcript
00:00Hi kids! Today we will learn how we can multiply decimal numbers. So let's start!
00:11We have to multiply 45 and 2.5 where 45 is a whole number and 2.5 is a decimal number.
00:26Let's see how we do it!
00:29First we will consider the decimal number as a whole number and do the simple multiplication.
00:38Multiplying 45 with 25 we got 1,125.
00:46Now our decimal number was 2.5. We have to see how many digits we have in the decimal number.
00:57Here we have only one digit after decimal point.
01:02So put decimal in our answer which is 1,125 after one digit from right.
01:13So putting decimal after one digit from right we get the answer.
01:20So our answer is 112.5.
01:27Now let's take another example.
01:31We have to multiply 233 with 6.80 where 233 is a whole number and 6.80 is a decimal number.
01:49Let's see how we do it!
01:52First we will consider the decimal number as a whole number.
01:576.80 and 6 point are one and the same thing.
02:03So take it as 6.8 and consider 6.8 as 68 and then do the simple multiplication.
02:16We will get 15,844.
02:22Now our decimal number was 6.8. We have to see how many digits we have in the decimal number.
02:33Here again we have only one digit after the decimal number.
02:39So put decimal in our answer.
02:44So 1584.4 is our answer.
02:51Now you can put commas in your answers too.
02:56Put a comma after three digits from right in the whole number part.
03:02So we will put comma after five as 485 are the three digits from right.
03:11Now let's take another example.
03:14We will multiply 44.5 with 3.45.
03:21Here both the numbers are decimal one.
03:25Let's see how we do it!
03:27First of all consider both the decimal numbers as whole numbers and do the simple multiplication.
03:36That is take 44.5 as 445 and take 3.45 as 345 and do the simple multiplication.
03:55Multiplying 445 with 345 we will get 153,525.
04:09Now it's time to put decimal in it.
04:13Our decimal numbers were 44.5 and 3.45.
04:20And we have to see how many digits in total we have in both the decimal numbers after decimal point.
04:29We have three digits in total after the decimal points.
04:34One in 44.5 and two digits in 3.45.
04:42So we will put that decimal in our answer which is 153,525 after three digits from right.
04:55So this is our answer 153,525.
05:03So kids isn't it simple?
05:05You just have to multiply the decimal number as whole number.
05:11And later on count the number of digits in total you have in decimal number.
05:17After the decimal point and put decimal in the product after the digits you counted from right.
05:25Now let's solve one more problem.
05:29We have to multiply 356.50 by 3.45.
05:38Let's do it.
05:41We have to do first we have to consider this number as whole numbers.
05:48Consider 356.50 as 3565 and .50 and .5 is one and the same thing.
06:02Zeros or the rightmost zeros in a decimal number does not matter.
06:09Consider 3.45 as 345.
06:14Now multiply these numbers.
06:17That is multiply 3565 with 345.
06:24And here we have the product.
06:27Now count the number of decimal places.
06:30That is count the number of digits in total in both the number that exists after the decimal point.
06:38We have one digit in 356.50 and two digit in 3.45.
06:48So we will put decimal after three digits from right in the product.
06:55So putting decimal after three digits from right.
06:591229.925 is our answer.
07:06And we can put commas too after three digits from right in the whole number.
07:13That is we will put commas here and we pronounce it as 1229.925.
07:24So kids today we learned how we can multiply decimal numbers with whole numbers.
07:31And decimal numbers with decimal numbers.
07:36Now you may go ahead and take a quiz to learn more.
07:40Bye-bye.