Exercise 1.2 - Chapter 1 Number Systems Term 3 7th Maths Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Ex $1.2$
Question $1 .$
Add by using grid $0.51+0.25$.
Solution:
Here $0.51=\frac{51}{100}$ and $0.25=\frac{25}{100}$
First we shade the region $0.51$ and then $0.25$.

The sum is the total shaded area. $0.51+0.25=0.76$

Question $2 .$
Add the following by using place value grid.
(i) $25.8+18.53$
(ii) $17.4+23.435$
Solution:
(i) $25.8+18.53$.
Using place value grid.

\text { Therefore } 25.8+18.53=44.33

(ii) $17.4+23.435$
Lets use the place value grid.

Therefore $17.4+23.435=40.835$

Question $3 .$
Find the value of $0.46-0.13$ by grid model.
Solution:
Here $0.46=\frac{46}{100}$ and $0.13=\frac{13}{100}$

Shading the region $0.46$ and then crossing out $0.13$ from the shaded area. The left out shaded region without cross marks is the difference. So $0.46-0.13=0.33$
 

Question $4 .$
Subtract the following by using place value grid, (i) $6.567$ from $9.231$ (ii) $3.235$ from 7
Solution:
(i) Let as use place value grid

Therefore $9.231-6.567=2.664$
(ii) Let as use place value grid.

Therefore $7-3.235=3.765$

Question $5 .$
Simplify: $23.5-27.89+35.4-17$.
Solution:
$23.5-27.89+35.4-17=14.01$
 

Question 6 .
Sulaiman bought $3.350 \mathrm{~kg}$ of Potato, $2.250 \mathrm{~kg}$ of Tomato and some onions. If the weight of the total items are $10.250 \mathrm{~kg}$, then find the weight of onions?
Solution:
Weight of Potato $=3.350 \mathrm{~kg}$
Weight of Tomato $=2.250 \mathrm{~kg}$
Total weight of Potato and Tomato $=(3.350+2.250 \mathrm{~kg})$
$=5.600 \mathrm{~kg}$
Weight of potato, tomato and onions $=10.250$
Weight of potato and tomato $=5.600$
$\therefore$ Weight of onions $=(10.250-5.600) \mathrm{Kg}=4.650 \mathrm{Kg}$
Weight of onions $=4.650 \mathrm{Kg}$

Question $7 .$
What should be subtracted from $7.1$ to get $0.713$ ?
Solution:
To get the number to be subtracted
We have $7.1-0.713=6.387$
$\therefore$ The number to be subtracted $=6.387$
 

Question $8 .$
How much is $35.6 \mathrm{~km}$ less than $53.7 \mathrm{~km}$ ?
Solution:
To get the answer we must subtract $53.7 \mathrm{~km}-35.6 \mathrm{~km}=18.1 \mathrm{~km}$

So $35.6 \mathrm{~km}$ is $18.1 \mathrm{~km}$ less than $53.7 \mathrm{~km}$.
 

Question $9 .$
Akilan purchased a geometry box for ₹ $25.75$, a pencil for ₹ $3.75$ and a pen for ₹ $17.90$. He gave ₹ 50 to the shopkeeper. What amount did he get back?
Solution:
Cost of geometry box $=₹ 25.75(+)$
Cost of Pencil box $=₹ 3.75$

Question $10 .$
Find the perimeter of an equilateral triangle with a side measuring $3.8 \mathrm{~cm}$.
Solution:
Perimeter of an equilateral triangle $=($ Side $+$ Side $+$ Side $)$ Sq. units.
Given side $=3.8$
$\therefore$ Perimeter $=3.8+3.8+3.8$
Perimeter of the triangle $=11.4 \mathrm{~cm}$

Objective Type Questions
Question 1 .
$1.0+0.83=$ ?
(i) $0.17$
(ii) $0.71$
(iii) $1.83$
(iv) $1.38$
Answer:
(iii) $1.83$

Question 2.

$7.0-2.83=$ ?
(i) $3.47$
(ii) $4.17$
(iii) $7.34$
(iv) $4.73$
Answer:
(ii) $4.17$

Question 3 .
Subtract $1.35$ from $3.51$
(i) $6.21$
(ii) $4.86$
(iii) $8.64$
(iv) $2.16$
Answer:

(iv) $2.16$
 

Question $4 .$
Sum of two decimals is $4.78$ and one decimal is $3.21$ then the other one is
(i) $1.57$
(ii) $1.75$
(iii) $1.59$
(iv) $1.58$
Answer:
(i) $1.57$

The difference of two decimals is $86.58$ and one of the decimal is $42.31$ Find the other one
(i) $128.89$
(ii) $128.69$
(iii) $128.36$
(iv) $128.39$
Answer:
(i) $128.89$