Keywords: Subtract, Difference, Balance

__Subtraction upto 99 with regrouping__

** **

__Recall__

i) Subtract
the following two-digit numbers.

ii) Two squirrels
collected nuts in the hollow of tree trunk.

Listen to their conversation.

Can you help the
squirrels to find the number of nuts that are left?

Total number of
nuts = 58

To find the
remaining number of nuts at the end of the first day, we need to subtract 12
from 58.

Continue subtracting successively for finding the number of nuts that are left at the end of second and third day complete the subtraction procedure.

__Travel Through__

Each of the four friends
Kavin, Kavini,Thirumagan and Sudar collected tamarind seeds and made geometrical
shapes using the seeds.

**Keywords: **Subtract, Difference, Balance

The number of seeds used by them are tabulated as
follows:

Kavin takes 22 seeds and used 9 seeds for making a triangle.

How many seeds are
left with him?

Sudar takes 54
seeds and used 38 seeds to make a rectangle. Find the number of seeds left with
her? **16 seeds left**

**Teacher’s
Note:**** **Teacher can motivate children to frame
different subtraction questions and subtract them** **using the information
given in the above table.

__Learn__

**Subtract using seeds**

Kavin
make a triangular shape using the seeds collected by him. Observe the table, write
the subtraction fact to find the number of seeds left with him.

To find
the number of seeds left with Kavin, we need to subtract the number of seeds
used from the number of seeds taken by him.

Let us
subtract 9 from 22 using the seeds followed by the subtraction procedure. Take
22 seeds into groups of tens and ones.

Step
1: Subtract the ones

Represent
22 as 2 tens and 2 ones and cancel 9 seeds from ones.

Step
2: Regroup by converting tens to ones

We need
to take away 9 seeds so we subtract the ones. We cannot subract 9 ones from 2
ones. So, we should regroup the seeds to overcome the shortage of seeds. For
that 1 ten is changed into 10 ones.

Step
3: Subtract the ones

Subtract
9 ones from 12 ones.

Step
4 : Subtract the tens.

Now
subtract tens. There is no tens to subtract. So 1 ten is to be written.

Hence, the number of seeds left with Kavin is
13.

__Learn__

**Subtraction using abacus**

Sudar collected 54
seeds and used 38 seeds to form a rectangle.

How many seeds are
left with her?

To find the number
of seeds left with Sudar we shall subract 38 from 54. We can do the subtraction
54-38 using abacus followed by the subtraction procedure. 54 has 5 tens and 4 ones.

So, put 5 green beads in tens place and 4 red beads
in ones place. To take away 38 from 54 we need to take away 3 tens and 8 ones
from 5 tens and 4 ones.

Step
1: Subtract ones

We
cannot subtract 8 ones from 4 ones.

So exchange 1 ten as 10 ones.

So we have

Step
2: Cancel 8 ones from 14 ones

Now we can subtract 8 ones from 14 ones.

Step
3: Subtract tens

Subtract 3 tens from 4 tens.

So, the number of beads left with Sudar is 16.

__Practice__

1. How many more
seeds were used for making rectangle than triangle ?

2. Thirumagan
collected 24 seeds and used 16 seeds. How many seeds are left with him?

24 –
16 = 8

3. Kavini used 18
out of 30 seeds collected by her. What is the difference?

30−18=12

4. What is the difference in the number of seeds used by
kavin and kavini?

Kavini: 18 seeds

Kavin: 9

Difference: 18 – 9 = 9

__Practice__

Subtract the following two-digit numbers.

32 – 28 = __4__

94 – 59 = __35__

72 – 46 = __26__

46 – 17 = __29__

50 – 36 = __14__

85 – 67 = __18__

__Think Like a Mathematician__

**Write the missing numbers in the boxes below.**

29 + 0 = 29,

29 − 0 = 29

__Try This__

Find the missing digits in each of the
subtraction facts.

__Know more__

i) We can check the
subtraction process in two ways.

Consider the
subtraction fact 53 – 36=17.

i) By adding: 36 + 17
= 53

ii) By subtracting:
53 – 17 = 36

Given two numbers
53 and 36. When 36 is subracted from 53, we get 17. To verify the answer we can
either add the number 36 and 17 to get the given number 53 or subract 17 from
53 to get the other number 36.

ii) When we subtract 0 from any number we get the same
number.

It means we did not take away anything from the number.

iii) When a number is subtracted from itself it gives 0.

It means we have taken away completely from the given
number.

__Mental maths__

**1. Kamal fixed 56
tubelights in a party hall. If 18 tubelights were fused, then how many
tubelights were used? **

Ans :

56 − 18 = 38 tubelight

**2. A factory
produced 95 cars in a day. How many cars were unsold if 37 were sold?**

95 −
37 = 58 cars

**3. Kumar walked 23
steps out of 90 steps to reach a shop. How many more steps he has to walk to
reach the shop?**

23 −
90 = 67 steps

**4. Kamali had 31
rupees with her. She bought a pen for 15 rupees. She saved the remaining
amount. Find the amount saved by her.**

31 −
15 = 16 rupees

**5. In a class of 42 students, 26 are girls. How many are
boys?**

42 − 26 = 16 boys

Tags : Numbers | Term 2 Chapter 2 | 2nd Maths , 2nd Maths : Term 2 Unit 2 : Numbers

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2nd Maths : Term 2 Unit 2 : Numbers : Subtraction upto 99 with regrouping | Numbers | Term 2 Chapter 2 | 2nd Maths

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