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# Summary

7th Maths : Term 3 Unit 1 : Number System : Summary

Summary

To round a decimal

* First underline the digit that is to be rounded. Then look at the digit to the right of the underlined digit.

* If that digit is less than 5, then the underlined digit remains the same.

* If that digit is greater than or equal to 5, add 1 to the underlined digit.

* After rounding of, ignore all the digits after the underlined digit.

● Adding zeros at the right end of decimal digits will not change the value of the number.

● Zeros are added at the right end of decimal digits of a decimal number that are to be added or subtracted.

● The number of decimal digits in the product of two decimal numbers is equal to the sum of decimal digits that are multiplied.

● When a decimal number is multiplied by 10, 100 or 1000, the digits in the product are same as in the decimal number but the decimal point in the product is shifted to the right by as many places as there are zeros followed by 1.

● When a decimal number by 10, 100 and 1000, the digits of the number (Dividend) and the obtained decimal number after division are the same but the decimal point in the obtained decimal number after division is shifted to the left by as many places as there are zeros followed by 1.

ICT Corner

Number system

Expected outcome

Step – 1

Open the Browser and type the URL Link given below (or) Scan the QR Code. GeoGebra work sheet named “Decimal_NumberLine” will open. Click on “divide the scale” and “further divide”

Step - 2

Move the arrows pointing downwards and click check box, see the fraction and decimals of the position. Also click “Add 1 more” to the given decimal number and check.