Showing posts with label class7-maths. Show all posts
Showing posts with label class7-maths. Show all posts

Tuesday 23 May 2017

CBSE Class 7 Maths - Data Handling - NCERT EXERCISE 3.4 (#cbsenotes)

Data Handling

EXERCISE 3.4
CBSE Class 7 Maths
CBSE Class 7 Maths - Data Handling - NCERT EXERCISE 3.4 (#cbsenotes)


Q1: Tell whether the following is certain to happen, impossible can happen but not certain.
(i) You are older today than yesterday.
(ii) A tossed coin will land heads up.
(iii) A die when tossed shall land up with 8 on top.
(iv) The next traffic light seen will be green.
(v) Tomorrow will be a cloudy day.

Answer:
(i) It is certain to happen.
(ii) It can happen but not certain.
(iii)It is impossible.
(iv) It can happen but not certain.
(v)  It can happen but not certain.


Sunday 7 May 2017

CBSE Class 7 Maths - Integers - NCERT Exercise 1.3 (#cbsenotes)

Integers

EXERCISE 1.3
CBSE Class 7 Maths
CBSE Class 7 Maths - Integers - NCERT Exercise 1.3 (#cbsenotes)



Q1: Find each of the following products:
(a) 3 × (–1)
(b) (–1) × 225
(c) (–21) × (–30)
(d) (–316) × (–1)
(e) (–15) × 0 × (–18)
(f) (–12) × (–11) × (10)
(g) 9 × (–3) × (– 6)
(h) (–18) × (–5) × (– 4)
(i) (–1) × (–2) × (–3) × 4
(j) (–3) × (–6) × (–2) × (–1)


Answer:
(a) 3 × (–1) = = –3

(b) (–1) × 225 = -225

(c) (–21) × (–30) = 630

(d) (–316) × (–1) = 316

(e) (–15) × 0 × (–18) = 0

(f) (–12) × (–11) × (10) = 132 × 10 = 1320

(g) 9 × (–3) × (– 6) = 9 × 18 = 162

(h) (–18) × (–5) × (– 4) = 90 × (–4) = –360

(i) (–1) × (–2) × (–3) × 4 = –6 × 4 = -24

(j) (–3) × (–6) × (–2) × (–1) = 18 × 2 = 36


Thursday 4 May 2017

CBSE Class 7 Maths - Integers - NCERT Exercise 1.2 (#cbsenotes)

Integers

EXERCISE 1.2
CBSE Class 7 Maths

CBSE Class 7 Maths - Integers - NCERT Exercise 1.2 (#cbsenotes)

Q1: 1. Write down a pair of integers whose:
(a) sum is –7
(b) difference is –10
(c) sum is 0

Answer:
(a) One such pair whose sum is -7 = -4 + (-3) = -7
(b) One such pair whose difference is -10 = -3 - 7 = 10
(c) One such pair whose sum is 0 = -5 + 5 = 0

Saturday 24 December 2016

CBSE Class 7 - Maths - CH4 - Simple Equations -Worksheet (#cbsenotes)

Simple Equations

Image credits: wikimedia

Worksheet

Worksheet based on NCERT Chapter on Simple Equations


Fill in the blanks

The equation 2x - 5 - 20 is an example of ___________ equation.

The degree of an unknown means the _________ of the unknown.

(a + b)2 = a2 + b2 + 2ab is an example of ________.

A quantity which has a fixed numerical value is called _________.

If RHS and LHS expressions are interchanged will the equation remain ______ (same/different).

While solving an equation if we add a quantity to one side, we must ________ the same quantity to the other side.

Thursday 18 February 2016

CBSE Class 7 - Maths Quiz (2016)

Maths Quiz


CBSE Class 7 - Maths Quiz (2016)

MCQs


Q1: The next two terms of the sequence are:
    7, 14, 28, 56, ...

(a) 72, 96
(b) 112, 224
(c) 96, 192
(d) 72, 144


Q2: The probability of getting a consonant from the word "MISSISIPI" is ________?

(a) 4/9
(b) 5/9
(c) 2/3
(d) 2/9



Q3: A parallelogram has ________

(a) No line of symmetry
(b) One line of symmetry
(c) Two lines of symmetry
(d) Three lines of symmetry



Q4: The measures of an angle supplement to the angle of 70° is ______.

(a) 20°
(b) 110°
(c) 70°
(d) 160°


Q5: Anu wanted to score 26 points in the game of cards, but ends up only 8/3 points. By how many points did she fail short?

(a) 70/3
(b) 16/5
(c) 64/3
(d) 62/5

Sunday 23 December 2012

CBSE Class 7 - Maths - Comparing Quantities (NCERT Ex 8.3) - Profit and Loss and Simple Interest

Comparing Quantities
Profit & Loss and Simple Interest
CBSE Class 7 - Maths - Comparing Quantities (NCERT Ex 8.3) - Profit and Loss and Simple Interest

Important points
Simple Interest
1. C.P. = Cost Price (Amount at which goods are purchased)
2. Sales Tax, VAT, cartage etc.are included in cost price.
3. S.P. = Selling Price (Amount at which goods are sold)
4. If SP > CP then it is Profit or Gain. Profit = SP - CP
5. If CP > SP then it is Loss. Loss = CP - SP
6. Profit of Loss per cent is always calculated on the cost price.


Friday 14 December 2012

CBSE Class 7 - Maths - CH8 - Comparing Quantities (Percentage, Ex 8.2)

Comparing Quantities 
(Percentage)

Important Points

1. Per cent is derived from Latin word ‘per centum’ meaning ‘per or out of hundred
2. 25% = 25 out of hundred = 25/100 = 1/4 = 0.25
3. Graphically it can be represented as shown.
4.Fractions and decimals can be converted to percentages and vice versa.

Q1: Convert the following to per cents:





Answer:

Saturday 8 December 2012

CBSE Class 7 - Maths - CH8 - Comparing Quantities (Ratio and NCERT Ex 8.1)

Comparing Quantities(Ratio)
Ratio of Circumference: Diameter = π
image credits: openclipart

Important Points

1. In the ratio x:y (called as x is to y), x is called the first term or antecedent. y is called the second term or consequent.

2. While comparing two quantities, the units must be the same.

3. A ratio remains unchanged if both its terms are multiplied or divided by same non-zero number.

 

4. The ratio (p:q) is said to be in simplest form when HCF of p and q is 1.

NCERT Exercise 8.1

Q1: Find the ratio of:
(a) ₹ 5 to 50 paise
(b) 15 kg to 210 g
(c) 9 m to 27 cm
(d) 30 days to 36 hours

Thursday 1 November 2012

CBSE Class 7 - Maths - CH4 - Simple Equations (Ex 4.4)

Simple Equations 

(NCERT Exercise 4.4)

Important Points:
An equation which has only one variable whose power is one is called a SIMPLE EQUATION.

In a simple equation keeping only the variable in the LHS of the equation and moving the constant to RHS (right hand side) is called the method of TRANSPOSITION.

Rules for method of Transposition are:
  1. A positive constant in the LHS becomes a negative constant when it is taken to the RHS and vice versa.
  2. A negative constant in the LHS becomes a positive constant when it is taken to the RHS and vice versa.
  3. The coefficient of the variable in tbe LHS becomes t.he multiplicative inverse when it is taken to the RHS :and vice versa.
An equation remains the same if the LHS and the RHS are interchanged.

Friday 5 October 2012

Numbers Quiz (CTET/Class6/Class7/Class 8)

Numbers Quiz
(CTET/Class6/Class7/Class 8)

Q1: 2, 4, 6, 8, 10 ... are

(a) prime numbers
(b) even numbers
(c) odd numbers
(d) none of these

Q2: The roman number CD in decimal form is

(a) 100
(b) 500
(c) 400
(d) 0

Monday 16 April 2012

Rules of Divisibility

Rules of Divisibility
 
2: A number is divisible by 2 if the last digit (unit's digit) is even. e.g. 32, 459992

3: A number is divisible by 3, if the sum of digits of a number is divisible by 3.
    e.g. 252 = 2 + 5 + 2 = 9 ÷ 3 = 3 ∴ 252 is divisible by 3

4: A number is divisible by 4, if the last two digits of the number is divisible by 4.
    e.g. 81924 = since last two digits 24 is divisible by 4, hence the number.

5: A number is divisible by 5, if the last digit of the number is 0 or 5.
    e.g. 35, 200, 1005

6: A number is divisible by 6, if the number is divisible by both 2 and 3.

7: A number is divisible by 7, to check for this follow these steps:

Tuesday 15 November 2011

NTSE MAT Quiz-1 (Series completion)

Complete the following series:

1.  6,12,21,___,48,66
 (a) 33      (b) 38       (c) 40       (d) 45

2.  125,80,45,20,___
 (a)  5        (b)    8     (c) 10        (d)12

3.  22,24,28,___,52,84

 (a)  30        (b)   36      (c)    42     (d) 46

4. 1,3,3,7,6,13,10,___,15,31


(a)  25        (b)   27      (c)    21     (d) 30

5. 3,1,7,3,13,7,21,15,31,31,___,63,57


(a)    39      (b) 41        (c)  38       (d) 43

Monday 14 November 2011

NTSE SAT Quiz-7 (Maths)


Q1: The sides of a right triangle are a, a+d, a+2d with a and d both positive. What is the value of ratio a:d ?
(a) 1: 3
(b) 1:4
(c) 2:1
(d) 3:1

Q2: In a group of cows and hens, the number of legs was 14 more than twice the number of heads. the number of cows is:
(a) 5
(b) 7
(c) 12
(d) 14

Q3: Each edge of cube is increased by 50%. The percent increase in surface area of the cube will be:
(a) 50
(b) 125
(c) 150
(d) 300

Monday 7 November 2011

NTSE Maths Challenges

Following are the typical problems asked in NTSE, Oympiad Maths,  and other Mathematical based aptitude tests
(best viewed in Chrome or Firefox).

Q1: Ramesh walks from his home to Railway station at the rate of 5 kmph, he misses the train by 7 minutes. However, if he walks at the rate of 6 kmph, he reaches the station 5 minutes before the arrival of the train. Find the distance of the station from his home.

Answer: Let 'd' be the distance between Ramesh's house to Station.
We know that distance = speed x time.

If he walks at speed 5 kmph, let time taken be t1
⇒ t1 = d/5

Let the time t2 is taken when he walks with a speed of 6 kmph.

⇒  t2 = d/6

Since the time gap between two cases is 12 mins = 1/5 hrs
⇒ t1 - t2 = d/5 - d/6 = 1/5 hrs
⇒  6d - 5d = 6
⇒ d = 6km

Q2: Roma travels from place A to B and then from B to C.
From A to B Distance is 55 km which she covers with an average speed of 22 km per hour
It takes her 1 hour 30 minutes moving from B to C with an average speed 30 km per hour
Calculate her average speed over the whole of her journey from A to C.


Answer: We know that $ Time = Distance ÷ Speed

∴ Time taken from A to B = 55/22 = 2.5 hours  = 2 Hrs and 30 mins

Distance from A to B = Speed x Time = 20 x 1.5  = 45 km.  (note time taken from B to C is given as 1 Hrs 30 minutes i.e. 1.5 Hrs)

Average Speed = Total Distance  ÷ Total Time
∴  = (55+45) ÷ (1.5+2.5) = 100  ÷ 4 = 25 kmph

Wednesday 26 October 2011

Maths Challenges (Answers)

Maths Challenges (Answers)


See Maths Challenges (Questions)...

Answer1: When two distinct lines cut each other, they always meet at single point. These two lines can cut the circle maximum at four different points. Therefore, maximum number of intersection points is 5 i.e (d). Following figure explains this.


Answer 2:
Total possible outcomes are 16 i.e.
HHHH, HHHT, HHTH, HHTT, HTHH, HTHT, HTTH, HTTT, THHH, THHT, THTH, THTT, TTHH, TTHT, TTTH, TTTT
The catch here is at least as many heads as tails, such possibilities are 11.
$\Rightarrow$ the probability is $\frac{11}{16}$

Answer 3:
Here product is a prime number. Since we know prime number is divisible by self and number 1 only. So the only choice for m is 1.

Tuesday 25 October 2011

Maths Challenges (Questions)

Maths Challenges (Questions)

Q1:A circle and two distinct lines are drawn on a sheet of paper. What is the largest possible number of points of intersection of these figures?
    (a) 2        (b) 3      (c)  4    (d) 5
 
Q2: Reena tosses a coin four times. The probability that she gets at least as many heads as tails is
    (a) 5/6      (b) 3/8     (c) 11/16      (d) 5/8

Q3: Given that the product of two whole numbers m × n is a prime number, and the value of m is
smaller than n, find the value of m.

Q4: Jane has 9 boxes with 9 accompanying keys. Each box can only be opened by its accompanying
key. If the 9 keys have been mixed up, find the maximum number of attempts Jane must make
before she can open all the boxes.                     (Singapore Asia-Pacific Mathematical Olympiad Competition)

Q5: If 32 people were to enter a statewide singles tennis tournament, how many matches would be played, including the championship?

Q6: I have 2 vats each containing 2 mats. 2 cats sat on each of the mats. Each cat wore 2 funny old hats. On each hat lay 2 thin rats. On each rat perched 2 black bats. How many things are in my vats? (NCERT class 7 Maths Brain Teasers)

Q7: How many positive integers less than and equal to 999 are divisible by 7 but not by 11?

Q8(SMOPS): How many digits are there before the hundredth 9 in the following number
        9797797779777797777797777779......?

Q9(Olympiad): Suppose today is Tuesday. What day of the week shall it be 100 days from now?

Follow the link to see the answers Maths Challenges (Answers)