Lesson 16 a.

Lesson 16 a.. Decimals.

Understanding Decimals. Decimals offer a more simple way of expressing fractions . The decimal number uses a dot Consider first the number eg. 235. 86, this is read as 2 hundred and 35 point eight six 2 3 5 8 6.

Let us now look at another decimal number. 78 506, The is read as Seventy eight point five zero six. 7 8 5 0 6.

Rounding off decimals. In some cases we might be asked to round off a decimal number to either the nearest whole number or to the nearest tenths. For example to round off the number 45.36 to the nearest tenth. Step 1: See if this second decimal place is 5 or greater. In this case it is 6 which is greater than 5. If the second decimal place is less than 5 then the first decimal place remains unchanged. Step 2: If the second decimal place is 5 or greater, then we increase the first decimal place by 1. In this case we change the first decimal place from 3 to 4. Step 3: Write the rounded off number which would be 45.4.

Second example : Round off 75.87 to 1 decimal place. Step 1: look at the second decimal place which is 7 . Step 2: Since 7 is greater than 5 we increase the first decimal place from 8 to 9 Step 3: Write the rounded off number which is 75.9 Third example : Round off 45.83 to 1 decimal place Step 1 : look at the second decimal place which is 3 Step 2: Since 3 is less than 5 we do not change the first decimal place, hence the first decimal place remains as 8 Step 3 : write the new rounded off number which is 45.8.

Example 4 : Round off 26.82 to the nearest whole number. Note that we are asked for the NEAREST WHOLE NUMBER Step 1 : We look at the first decimal place which in this case is 8 Step 2: Since 8 is greater than 5 we increase the units from 6 to 7. Step 3 : Write the rounded off number as 27..

Example 5: Round off 46.56 to the nearest whole number. Step 1 : The first decimal place is 5 , so we increase the units by 1 Step 2 : The unit number is changed from 6 to 7 Step 3 : The new number is 47. Example 6: Round off 58.35 to the nearest whole number. Step 1 : First decimal place is 3 which is less than 5. Step 2: Unit remains unchanged Step 3: New number is 58.

Questions.