Joining Thousands || Class- 4 || Mathematics || Unit - 3 || Whiteboardweb

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 Maths puzzle

 

 

 

Arrange the consecutive numbers from 1 to 8 in the columns given below.The consecutive numbers should not come near.

 

 

 

 

 

 

 

 Try to find out another ways also .

 

 

1)Find the sum of the cosecutive numbers from 1 to 10 ?

 

 

1+2+3+4+5+6+7+8+9+10

 

 

 There are two easy ways to find the sum.

First way 

1,2,3,4,5,6,7,8,9,10

  

Add the first number and last number

 

1 + 10 = 11

 

 

Then multiply the answer with 5 

 

11 X 5 = 55

 

 

 

Another way

1,2,3,4,5,6,7,8,9,10

Multiply the fifth number with ten.

 

5 X 10 = 50

 

 

Add 5 to the answer.

 

50 + 5 = 55

 

 

 

2)What is the sum of the cosecutive numbers from 11 to 20 ?

11 + 20 = 31

 

31 x 5 = 155

 

 

or

 

 

15 x 10 = 150

 

150 + 5 = 155

 

 

 

3)What is the sum of the cosecutive numbers from21 to 30?

 

 

21+30 = 51

 

51 x 5 = 255

 

 

or

 

 

25 x 10 = 250

 

250 + 5 = 255

 

 

Activity

What is the sum of 10  cosecutive numbers from 41?

 

 

Large and small

1)The sum of the largest two digit number and the largest one digit number

 

 

99 + 9 = 108

 

 

 

2)The sum of the largest three digit number and largest two digit number

 

 

999 + 99 =

 

 

 

3)The sum of the largest four digit number and the largest three digit number

 

 

9999 + 999=