# NCERT: Math-Magic Solutions for Class-3, Chapter-7: Time Goes on

**Time Goes on ** with the concept of time. This chapter have exercises on reading calendar, Reading time in hours, chronology of events.

The solutions for Math-Magic Chapter-7 have been created and verified by our experienced subject matter experts, according to the CBSE syllabus and guidelines of NCERT. For practice, our subject matter experts have created very interactive, activity-based, and Image-based worksheets on these topics to enhance learning.

Download Chapter 7 Time Goes on in PDF format for free here.

**Chapter 7: Time Goes On**

**Question 1 : **As the sun sets ______Sumana wakes up. What a lovely evening! _______She washes her face fast in 2hours __________and runs out. She goes straight to the bird's nest. She has been watching the eggs for the last few months___________. She was waiting for the baby birds to come out. But before she can blink her eyes, in a week ________ a cat jumps onto the tree. The mother bird cries loudly and Sumana rushes to shoo the cat away. As the cat jumps, it hits the big green mango. Dhum! ... In two days _____________.it is on the ground ! Oh, how sad! The mango is still not fully ripe. It needed one more year ________ to become sweet. Suddenly Sumana's sister calls out — Are you still not hungry? Has your stomach clock gone to sleep? Come and eat hot upma for dinner _____________. Wasn't that funny? You must have guessed that the coloured words are wrong. Choose the correct word from the box given below and write it next to the wrong word.

days rises seconds morning

breakfast moment minutes week

**Answer : **As the sun rises Sumana wakes up. What a lovely morning! She washes her face fast in 2 minutes and runs out. She goes straight to the bird's nest. She has been watching the eggs for the last few days. She was waiting for the baby birds to come out. But before she can blink her eyes, in a moment a cat jumps onto the tree. The mother bird cries loudly and Sumana rushes to shoo the cat away. As the cat jumps, it hits the big green mango. Dhum! ... In two >seconds, it is on the ground! Oh, how sad! The mango is still not fully ripe. It needed one more week to become sweet. Suddenly Sumana's sister calls out — Are you still not hungry? Has your stomach clock gone to sleep? Come and eat hot upma for breakfast.

**How Long does it Take?**

**Question 2 : **Think of many different things that can take different times. Make your table as long as you can.

**Answer : **There are many tasks you do in a day. Get some ideas from the same. A sample answer is:

**Clap! Clap! — Before you Catch**

**Question 3 : **How many of you can speak and stamp at the same time?

**Answer : **Do it by yourself. Most of the people can speak and stamp at the same time.

**Question 4 : **Have you heard people playing a tabla or the drums? Find out a few different beats they play. Also ask what 'bols' they say for the beats they play.

**Answer : ** Do it by yourself as directed. Many people can play tabla or drums. Different beats of tabla are Ektal and Chautal ,Jhaptal (or Japtal), Keherwa, Rupak (Mughlai/Roopak).

**How Old are We?**

**Question 5 : **How Old are We?

**Answer : **Do it yourself.

**Question 6 : **

Irfan's mother is twice as old as him. She is also 20 years older than him. Guess the ages of Irfan and his mother.

**Answer : **Since the mother is twice as old as him and he is 20 years old, twice his age will be 40 years. Hence, the age of Irfan’s mother is 40 years.

**Question 7 : **How many full moons have passed since you were born?

**Answer : **Do it by yourself by discussing it with your parents. The difference between one full moon to another full moon is 30 days or more precisely 29 days, 12 hours, and 44 minutes.

**Birth Certificate**

**Question 8 : **Look at the birth certificate of Bincy.

(1) 2/5/2002 shows that Bincy was born on 2 in the year 2002.

(2) How old will Bincy be on 2 May 2008?

(3) How old will she be in the year 2052?

(4) On what date will she be eight years old? Write in numbers.

(5) How many months old was Bincy on 2 August 2002?

(6) How many years old is Bincy now?

(7) After how many months of her birth was the certificate issued?

(8) What is the registration number of her certificate?

**Answer : **

(1) 2/5/2002 means 2 May 2002. So, 2/5/2002 shows that Bincy was born on 2nd May 2002.

(2) Subtract 2002 from 2008 to get the number of years from 2002 to 2008.

2008

-2002

6

Hence, Bincy will be 6 years old on 2nd May 2008.

(3) Subtract 2002 from 2052 to get the number of years from 2002 to 2052.

2052

-2002

50

Hence, Bincy will be 50 years old on 2nd May 2052.

(4) Add 8 with 2002 to get the Bincy’s age in 8 years.

2002

+ 8

2010

So, Bincy will be 8 years old on 2nd May 2010.

(5) Since she was born on 2nd May 2002, she will be 3 months old on 2nd August 2002.

(6) From May to December there are 8 months and difference between 2002 to 2021 is 19 years Hence, she is 19 years 8 months old.

(7) She was born on 2nd May 2002 and the certificate was issued on 5th August 2002. Since there are 3 months from May to August, the certificate was issued after 3 months of her birth.

(8) The Registration Number of her certificate is 815/02

**Let's Deliver Letters**

**Question 9 : **When were you born? Write your date of birth in numbers. Do you have a birth certificate? Ask your parents and make one for yourself.

**Answer : **Do it by yourself.

**Calendar**

**Question 10: **

a) How many months does a year have?

b) List the months which have 30 days.

c) List the months which have 31 days.

d) How many days are there in the month of February this year?

e) How many days make a week?

f) How many weeks are there in July? Is it true for all the months?

g) In which month did you come to Class III?

h) Make a circle on these dates in the calendar:

26th January

14th November

31st December.

i) Is there something special about these dates?

j) Fill in the blanks with the correct year:

1. Which year was it two years back?

2. In which year were you in Class II?

3. Which year will be the next year?

s 4. Which year will come after 3 years?

**Answer : **

a) A calendar has 12 months.

b) There are 4 months which have 30 days. They are April, June, September, and November.

c) There are 7 months which have 31 days. They are January, March, May, July, August, October, and December.

d) This year there are 29 days in the month of February.

e) After counting from the calendar, it is clear that there are 7 days in a week.

d) In the month of July there are 4 weeks. It is true for almost all the months.

e) Do it by yourself.

f) In the calendar of 2020 the given dates are marked.

g) These dates are special. The reasons are mentioned below.

26th January -Republic Day of India

14th November – Children’s Day

31st December – Last day of a year.

h) 1. This is the year 2020. Two years back it was the year (2020 – 2)

= year 2018

2. In 2020, you are in class III. One year back you were in class II. So, you were in class II in the year (2020 – 1) = 2019 3. The next year will be (2020 + 1) = 2021

4. After 3 years will be = (2020 + 3) = 2023

**Which Festival comes First?**

**Question 11 : **Given below are some festivals we celebrate during the year. Look at the calendar (2020) to find the days on which these fall.

**Answer : **The correct answer is:

**Question 12 : **Arrange the festivals in the order in which they come in the year

**Answer : ** The correct answer is.

**Question 13 : **(i)Which festival comes in the beginning of the year?

(ii) Which festival comes at the end of the year?

**Answer : ** According the calendar

(i) Pongal comes in the beginning of the year.

(ii) Christmas Day comes at the end of the year.

**Question 14 : **Which is the number in the centre of the square?

**Answer : ** From the above picture it is clear that 13 is the number in the centre of the square.

**Question 15 : **How many such lines can you draw?

**Answer : **Since

6 + 13 + 20 = 39

12 + 13 + 14 = 39

Four such lines can be drawn as:

5 + 13 + 21 = 39

19 + 13 + 7 = 39

**Question 16 : **What do you notice?

5 + 13 + 21 =

6 + 13 + 20 =

19 + 13 + 7 =

12 + 13 + 14 =

**Answer : ** Since

5 + 13 + 21 =18 + 21 = 39

6 + 13 + 20 = 19 + 20 = 39

19 + 13 + 7 = 19 + 20 = 39

12 + 13 + 14 = 25 + 14 = 39

The sums of all of the numbers are same.

**Question 17 : **Now look at the calendar of 2020. Also look for the present month and draw any similar square in your notebook. Does the magic work for these?

**Answer : **Since

8 + 16 + 24 = 48

22 + 16 + 10 = 48

15 + 16 + 17 = 48

9 + 16 + 23 = 48

**Question 18 : **Is this magic possible on a 10 × 10 number chart? Go to the chapter 'Fun with Numbers' and check.

**Answer : **By the diagonal lines:

10 + 19 + 28 + 37+ 46 + 55 + 64 + 73 + 82 + 91= 505 1 + 12 + 23 + 34 + 45 + 56 + 67 + 78 + 89 + 100 = 505 But 95 + 85 + 75 + 65 + 55 + 45 + 35 + 25 + 15 + 5 = 500 ≠ 505 96 + 86 + 76 + 66 + 56 + 46 + 36 + 26 + 16 + 6 = 600 ≠ 505 Similarly,

51 + 52 + 53 + 54 + 55 + 56 + 57 + 58 + 59 + 60 = 600 ≠ 505 41 + 42 + 43 + 44 + 45 + 46 + 47 + 48 + 49 + 50 = 500 ≠ 505 Hence, the magic is not possible for a 10 × 10 number chart.

**Question 19 : **See if this magic works for other lines which have five numbers. What about five numbers on a slanting line? Try this trick with your family and friends. Can you find other magic patterns in the calendar?

**Answer : ** The same pattern is followed for these five numbers also.

2 + 9 + 16 + 23 + 30 = 80

and 16 × 5 = 80

The numbers on the slanting lines are shown below.

29 +23 + 17 + 11 + 5 = 85 = 17 × 5

30 + 24 + 18 + 12 + 6 = 90 = 18 × 5

31 + 25 + 19 + 13 + 7 = 95 = 19 × 5

Yes. There is another magic pattern in the calendar.

8 + 9 + 10 + 11 + 12 + 13 + 14 = 77 = 11 × 7

Similar patterns can be seen in other rows too.

**Complete the Calendar**

**Question 20 : **for August 2020

(i)Colour all the Sundays in red.

(ii)On which day does this month end?

(iii)Write the number of days in this month.

(iv)What day is it on 13th August?

(v)What is the date on the second Saturday?

(vi)Is the 21st a Sunday?

(vii)What is the day on the 29th? What will be the date on the same day next week?

(viii)How many Thursdays are there in this month?

**Answer : **

(i)After colouring the Sundays on the calendar, you get

(ii)The month ends on Monday (31st august).

(iii)There are 31 days in this month.

(iv)13th August is Thursday.

(v)The date of the 2 nd Saturday is 08.08.2020.

(vi)No, 21st August is not a Sunday. It is Friday.

(vii)29th August is Saturday.

The same day next week will be (29 + 7) = 36 = 31 + 5 Hence, the next week’s same day will be 5th September 2020. It is our Teacher’s day.

(viii)There are a total of 4 Thursdays in the month of August.

**Question 21 : **

(i)Which months in the calendar (2020) have 5 Sundays?

(ii)Is there any other day in any month which comes 5 times?

(iii)Can there be 6 Sundays in a month? Why?

**Answer : ** From the calendar of 2020, it is clear that

(i)There are 4 months in the calendar which have 5 Sundays. They are March, May, August, and November.

(ii)Yes, there are different days in different months which come 5 times. Here is a list of them given in the below table.

Months | Repeating days(5 times) |
---|---|

January | Wednesday, Thursday, Friday |

February | Saturday |

March | Sunday, Monday, Tuesday |

April | April |

May | Friday, Saturday, Sunday |

June | Monday, Tuesday |

July | Wednesday, Thursday, Friday |

August | Saturday, Sunday, Monday |

September | Tuesday, Wednesday |

October | Thursday, Friday, Saturday |

November | Sunday, Monday |

December | Tuesday, Wednesday,Thursday |

(iii)No, there cannot be 6 Sundays in a month. Because there are 4 weeks in a month. So, there can be a maximum of 5 Sundays

**Question 22 : **Some things that happened in her life are given below. Mark these on her timeline. For example, when she was 5 years old Pedki broke her foot. A is marked at 5 on the timeline.

A. Broke her foot

B. Lost one goat

C. Got married

D. Had her fourth child

E. First saw a police station

F. Learnt to read and write

G. Eldest daughter got married

**Answer : ** Here is the timeline of Pedki Devi after marking the memorable incidents that happened in her life.

**Question 23 : ** Mark on the timeline when she was born.

**Answer : ** Here is the answer.

**Question 24 : ** n the blank box draw a picture of Pedki as a new born baby

**Answer : ** Do it by yourself

**Question 25 : ** Make your own timeline. Ask people around you and mark at least one thing that happened in each year of your life.

**Answer : ** Here is an example given. This is the timeline of baby Ram up to his ten years.

1. In year one he started walking

2. In year two he started talking

3. In year three he started going to school

4. In year four he started swimming

5. In year five he is in class 1

6. In year six he is in class 2

7. In year seven he is in class 3

8. In year eight he is in class 4

9. In year nine he is in class 5

10.In year ten he is in class 6

**Question 26 : ** Make timelines of people you admire. These can be your family, friends, teachers, etc.

**Answer : ** Do it by yourself

**One Day in the Life of Kusum**

**Question 27 : ** Write down the time for each picture. For some pictures, the time is already written and you must draw the hands on the clock. In others, you have to write the time shown by the clock.

**Answer : **

**Question 28: ** Now prepare a chart showing your own daily routine.

**Answer : **Do it by yourself