Decimal

What is a decimal? ,[object Object],[object Object]

About Decimals ,[object Object]

About Decimals ,[object Object],[object Object],ones tens hundreds thousands To the left of the decimal, all the numbers are whole numbers. Each column is worth ten times the column to its right.

About Decimals ,[object Object],[object Object],Ten thousandths thousandths hundredths tenths

Reading Decimals ,[object Object],[object Object]

Comparing Decimals ,[object Object],[object Object]

Comparing Decimals ,[object Object],[object Object],[object Object],[object Object]

Comparing Decimals ,[object Object],[object Object],[object Object]

Rounding Decimals ,[object Object],[object Object]

Rounding Decimals ,[object Object],[object Object],[object Object]

Rounding Decimals ,[object Object]

Rounding Decimals ,[object Object],[object Object],[object Object],[object Object],Because we are rounding to the nearest hundredth, each of the numbers ends up with two digits behind the decimal. What if we had been rounding to the nearest tenth? (answer: Rounding to the nearest tenth leaves one decimal place. In the example: 1.3, 1.0, 4.9)

Adding & Subtracting Decimals ,[object Object],[object Object]

Subtracting Decimals ,[object Object],[object Object],[object Object],[object Object],[object Object],Annex a zero here so you can borrow.

Multiplying Decimals ,[object Object]

Multiplying Decimals ,[object Object],[object Object],[object Object]

Multiplying Decimals ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

WHOA! ,[object Object],[object Object],[object Object]

Dividing Decimals ,[object Object],[object Object],7 dividend divisor quotient Notice that the 7 is over the 6, not the 5. The quotient goes over the LAST digit you are working with.

Dividing Decimals ,[object Object],[object Object]

Dividing Decimals ,[object Object],[object Object],If these were whole numbers, you would say, “How many times will 12 go into 13?” But it’s harder to think of .12 and .13. If you could move the decimal of the divisor (.12) over 2 places, you would have a whole number. You can do that as long as you move the decimal of the dividend over 2 places as well.

Dividing Decimals ,[object Object],NOTICE: The decimal moved straight up from the dividend to the quotient. Lining up the number in the quotient and the dividend is VERY important because if they are wrong, your decimal will be in the wrong place. 12. 13.2 1.1 -12 1 2 -1 2 0

ALWAYS Check! ,[object Object],[object Object],1.1 x.12 22 11 .132 1 digit 2 digits 3 digits

Dividing Decimals ,[object Object],[object Object],[object Object]

Dividing Decimals ,[object Object],[object Object],First of all, let’s estimate how many .4’s it would take to make 1.25 .4 + .4 + .4 = 1.2 so it will take 3 groups of .4 plus a little more to make 1.25 .4 1.25

Dividing Decimals First, move the decimal in the divisor and the dividend. In this case, we have pulled down all our numbers, but we still have a remainder. DO NOT tack your remainder onto the end of your answer! 4. 12.5 3.1 -12 05 -4 1

Annexing Zeroes ,[object Object],[object Object],[object Object]

Annexing Zeroes- -8 20 -20 0 When you get a remainder of zero, you can stop pulling down zeroes. 4. 12.5 000 3.125 -12 05 -4 10

Check Your Work! The original problem was 1.25 ÷ .4. The quotient was 3.125 Check: 3.125 x .4 1.2500 3 digits 1 digit 4 digits Since 1.2500 = 1.25, our answer is correct.

Dividing Decimals ,[object Object],First, move the decimal. . Put the decimal on the quotient line. .3 5.56 3. 55.6

Repeating Decimals When you’ve pulled down all your numbers and you still have a remainder, you need to annex zeroes and keep going. 3. 55.6 18.5 -3 25 -24 16 -15 1

Repeating Decimals -9 10 From here on, no matter how many zeroes we pull down, we will always get 10 and the next number will always be 3. The 3 is repeating. 3. 55.6 000 18.533 -3 25 -24 16 -15 10

Repeating Decimals ,[object Object],[object Object],18.53

Get the “point”? ,[object Object],[object Object]

Decimal

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