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00:00NUMBERS
00:04FOUR-DIGIT NUMBERS
00:08In our previous classes, we have learned about two-digit and three-digit numbers.
00:15We know that the smallest two-digit number is 10.
00:20The largest two-digit number is 99.
00:25The smallest three-digit number is 100.
00:29The largest three-digit number is 999.
00:36Now, let us know about four-digit numbers.
00:41When you add 1 to the largest three-digit number, i.e., 999, we get a four-digit number.
00:52We read this as one thousand.
00:56In words, we write it as one thousand.
01:00One thousand is the smallest four-digit number.
01:05It stands in the fourth place in the place value chart.
01:10The largest four-digit number is 9999.
01:18FOUR-DIGIT NUMBER ON AN ABACUS
01:24Let us read about four-digit number with the help of an abacus.
01:29Count the number of beads in the spikes that shows 1s, 10s, 100s, and 1000s respectively.
01:40We have 5 beads in the 1s column.
01:44We have 2 beads in the 10s column.
01:48We have 3 beads in the 100s column.
01:52And, we have 4 beads in the 1000s column.
01:57The same numerals may be written in the place value chart like this.
02:04Four thousand, three hundred, and twenty-five.
02:10Now, let us try some examples.
02:14Let us arrange these four-digit numbers in the place value chart and write their number names.
02:22Six thousand, five hundred, and thirty-four.
02:27Write 4 in the 1s column.
02:30Write 3 in the 10s column.
02:34Write 5 in the 100s column.
02:37Write 6 in the 1000s column.
02:40Now, we have six thousand, five hundred, three 10s, and four 1s.
02:49We write it as six thousand, five hundred, and thirty-four.
02:57Next, we will take 8,987.
03:04Write 7 in the 1s column.
03:07Write 8 in the 10s column, 9 in the 100s column, and 8 in the 1000s column.
03:15So, we have eight thousand, nine hundred, eight 10s, and seven 1s.
03:24We write this as eight thousand, nine hundred, and eighty-seven.
03:32The next number is 3,475.
03:39Bring 5 to the 1s column, 7 to the 10s column, 4 to the 100s column, and 3 to the 1000s column.
03:52We have three thousand, four hundred, seven 10s, and five 1s.
04:01We write this as three thousand, four hundred, and seventy-five only.
04:10Next is 2,190.
04:17Bring 0 to the 1s column, 9 to the 10s column, 1 to the 100s column, and 2 to the 1000s column.
04:29We have two thousand, one hundred, nine 10s, and zero 1s.
04:39We write this as two thousand, one hundred, and ninety.
04:47Next is 5,566.
04:53Bring 6 to the 1s column, 6 to the 10s column, 5 to the 100s column, and 5 to the 1000s column.
05:06Now we have five thousand, five hundred, six 10s, and six 1s.
05:16We write this as five thousand, five hundred, and sixty-six.
05:24Let us write the numerals for the given number names.
05:291,987
05:33We have one thousand, nine hundred, eight 10s, and seven 1s.
05:41We write this as one nine eight seven.
05:487,566
05:53We have seven thousand, five hundred, six 10s, and six 1s.
06:01We write this as seven five six six.
06:084,567
06:14We have four thousand, five hundred, six 10s, and seven 1s.
06:24We write this as four five six seven.
06:29Next we will read the abacus and write the numerals and the number names.
06:36In this abacus we have six beads in the 1s column, three beads in the 10s column, two beads in the 100s column, and five beads in the 1000s column.
06:51We write this as five two three six.
06:56We write this in words as five thousand, two hundred, and thirty-six.
07:02In this abacus we have one bead in the 1s column, four beads in the 10s column, two beads in the 100s column, and three beads in the 1000s column.
07:17We write this as three two four one.
07:22We write this in words as three thousand, two hundred, and forty-one.
07:28Face value of a digit in a numeral.
07:32The face value of a digit in a numeral will remain the same at whatever place it stands.
07:40There will be no change in the value.
07:43Thus, in the numeral nine eight seven six, the face value of six is only six.
07:51The face value of seven is only seven.
07:55The face value of eight is only eight.
07:59And, the face value of nine is nine.
08:04Place value of a digit in a numeral.
08:09The place value of a digit in a numeral depends upon its position in the place.
08:16The place value of a digit in a numeral depends upon its position in the place value chart.
08:23Let us see an example by using a full digit number.
08:29First, let us arrange six thousand eight hundred and seventy-nine in the place value chart.
08:37The place value of nine will be nine ones which is equal to nine.
08:42The place value of seven will be seven tenths which is equal to seventeen.
08:48The place value of eight will be eight hundredths which is equal to eight hundred.
08:55And, the place value of six will be six thousandths which is equal to six thousand.
09:05Numerals in expanded form.
09:08A numeral when expressed as a sum of the place values of its digits is said to be in its expanded form.
09:17Let us see this with an example.
09:20Place the number nine eight seven six in the place value chart.
09:25Nine eight seven six is equal to nine thousandths plus eight hundredths plus seven tenths plus six ones
09:41which is equal to nine thousand plus eight hundred plus seventy plus six.
09:49This is called the expanded form of the number nine thousand eight hundred and seventy six.
09:57Successor of a number.
10:00The number that comes just after a particular number is called its successor.
10:06In the numerical order, the successor of a number is one more than the number.
10:13The successor of five is five plus one.
10:18That is six.
10:21The successor of twenty five is twenty five plus one.
10:27That is twenty six.
10:30The successor of one hundred and twenty five is one hundred and twenty five plus one.
10:38Which is one hundred and twenty six and so on.
10:44Predecessor of a number.
10:48The number that comes just before a particular number is called its predecessor.
10:54In the numerical order, the predecessor of a number is one less than the number.
11:02The predecessor of five is five minus one.
11:06That is four.
11:08The predecessor of twenty five is twenty five minus one.
11:13That is twenty four.
11:16The predecessor of one hundred and twenty five is one hundred and twenty five minus one.
11:23That is one hundred and twenty four.
11:29Comparison of numbers.
11:32Let us first learn the rules for comparison.
11:36Rule one.
11:38First compare the digits at the left most place in both the numbers.
11:43Rule two.
11:44If they are equal, compare the second digits from the left.
11:49Rule three.
11:51If the second digits from the left are also equal, then compare the third digits from the left.
11:59Rule four.
12:01Continue in the same way until you find unequal digits at the same place.
12:08Then find the number which is greater by comparing the unequal digits.
12:14Let us see an example.
12:17Compare eight seven six five and nine eight seven six.
12:24Both the numbers are four digit numbers.
12:27Compare the digits at the left most place.
12:31The digit is eight in the first number and nine in the second number.
12:37So you know nine is greater than eight.
12:42So nine thousand eight hundred and seventy six is greater than eight thousand seven hundred and sixty five.
12:53See another example.
12:56Compare eight seven six five and eight seven six four.
13:02Both are four digit numbers.
13:05Both have same number in the thousands place that is eight.
13:09Both have same number in the hundreds place that is seven.
13:15Both have the same number in tens place too that is six.
13:21Now let us see the ones place.
13:24Here the number is different.
13:27It is five in the first number and four in the second number.
13:33So eight thousand seven hundred and sixty five is greater than eight thousand seven hundred and sixty four.
13:44Ordering of Numbers
13:47There are two types of ordering numbers.
13:50Namely ascending order and descending order.
13:55The numbers are arranged using the comparison rules.
13:59When given numbers are arranged from the greatest to the smallest it is called the descending order.
14:07Example is eight thousand seven thousand six thousand five thousand and so on.
14:16When the given numbers are arranged from the smallest to the greatest it is called the ascending order.
14:22Example for this is one thousand two thousand three thousand four thousand and so on.