Place value System

Ascending and Descending Order of Numbers

We have seen that numbers have value based on the place in which they are present. Many times, we come across smallest and greatest of a given set of numbers in our activities.

For example, would you like to eat more or less of your favourite dish? Would you like to drink more or less of a cough medicine?

Ganesha likes to have more modakas. Help Ganesha choose the order of plates.          

Place-value of Three-Digit Numbers

Hundreds and More….

When we have more than 99 things to count what should we do?

Simple, we start our digits in a new column one place to the left of the anka (digit) in the tens place. A place left to the tens place is called the “hundreds place”. 

Hundreds	Tens	Units
1	1	०

Now, we show how many hundreds, tens and ones we have in each place respectively. Using this we can write as many numbers as we want now…

 

Number 132 has 1 Hundred 3 Tens and 2 Ones

What if we have zero in the tens place?

Place	Hundreds	Tens	Units
Value	most	more	less
	100	10	1

• The number system is based on ten digits (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). It is called Decimal Number System.
• Place or position of the digits goes from right to left starting from units, then tens place to the left of units, then hundreds place to its left.
• The value of a number remains the same at all times.
• Value of the number is 10x times more as we go left from the units’ place.
• Using this system large and small numbers can be written easily.

Order of Numbers (Ascending and Descending)

Show Harish's moves on the football field.

Harish was playing football in his school. He made the following moves with the ball in the field. Count and write the numbers in the squares where the arrow starts and ends. Count according to the spaces moved forward or backwards.  

1. He moved forward by 5 boxes from ______________ to ____________
2. He moved forward by 10 boxes from ____________ to _____________
3. Find the highest number box touched by the ball? ________________
4. Find the lowest number box touched by the ball? ________________
5. What is the last number in the field? _________________

Activity: Finding the Place-value

Number Exercise – Identify the ones, and tens place of a number.

Activities and Exercises

Activity 1

Draw on ground big squares (1 to 30) for pairs of students to play. One student is tagged units and the other tens and both are far apart. Teacher calls out a one- or 2-digit number. Students should instantly identify their units or tens tag and reach those squares within time. When the student group is large pair of students can be assigned specific 1 -10 rows in which the pair has to join when the number is called out.

Activity 2

Ten students are assigned 10 digits of units’ place (wearing a digit flash card). Another set of 10 students are assigned 10 digits of 10s place (wearing a digit flash card). The students form a circle randomly around the basket containing rubberbands. When a number is called those students join to form a pair in the middle and collect the rubberbands of their friend’s digit.

Suns and Blackholes

Choose any three skip countings for a game – 2s, 4s, 3s, 5s, 6s etc before game starts. Draw squares on the ground (1 to 40) marking suns and blackholes on random squares. Game can be played by 2 to 4 students simultaneously. First time display flash cards with any number below 20 and the child stands in that square. Subsequently call out “move by 3” all students in the square move forward by 3. Then say “move by 5” they count from their squares and move to that number. If they encounter a sun they additionally move 4 squares as bonus. If they encounter a black hole they move exactly by 10 backwards.  At least 2 different skip counts may be used in one game and one skip count for bonus.

Exercises

Skip Counting Charts.

Count by 2s and color them orange.

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	42	44	45	46	47	48	49	50

Count by 3s and color them yellow.

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	42	44	45	46	47	48	49	50

Count by 5s and color them green.

1	2	3	4	5	6	7	8	9	10
11	12	13	14	15	16	17	18	19	20
21	22	23	24	25	26	27	28	29	30
31	32	33	34	35	36	37	38	39	40
41	42	42	44	45	46	47	48	49	50

When even number is called out one student marks the square with that number, Odd number is identified and marked by another student.

1					6
								39
										51

Find Surya and Chandra in each row and their meeting point by counting backwards and forwards. Write the numbers and color boxes as shown in the grid starting from 1 ending at 99. This can be a field activity also for children.

Surya and Chandra are represented in each row by S and C.

1.   Identify the number in the grid on which they are located. Example row 1, Surya is on number 4 and Chandra on number 9.

2.   The number by which Surya has to be moved forward is given on the left

3.   The number by which Chandra has to be moved backwards is given on the right.

4.  Example – Count forward by 2 from 3 to 5 for Surya and color that cell yellow. Similarly count backwards by 3 from 9 to 6 for Chandra and color that cell green.

5.   Repeat this process for each row and find the pattern.