Bellwork Monday 8/13/18 Order these numbers from greatest to least 35.06, 35.7, 35.5, 35.849 Order 15, 14.95, 15.8, and 15.01 from least to greatest 1) 2) 14.95, 15, 15.01, 15.8 35.849, 35.7, 35.5, 35.06 First, line up the decimal points. 15 35.06 14.95 35.7 15.8 35.5 15.01 35.849 Finally, use place value to compare the decimals. Always start from the left!! 15.00 35.060 14.95 35.700 15.80 35.500 15.01 35.849 Next, annex zeros so that each number has the same number of decimal places. 15.00 35.060 14.95 35.700 15.80 35.500 15.01 35.849
Place Value
Decimal Word Names Decimal word names always end in “-th” or “-ths” one tenth four hundredths
Representing the Decimal The decimal is represented by the word “and” when writing and saying decimals in words. 2.1 = two and one tenth
How to write decimals numbers greater than one To write a number containing a whole number and decimal follow these steps: Write the whole number in words Write “and” for the decimal Write the numbers shown to the right of the decimal Write the last place a digit occupies in the decimal (the farthest right) 32.46 thirty-two and forty-six hundredths 32.46 = thirty-two and forty-six hundredths
Rounding Decimal Numbers Sometimes close enough is good enough!
The Rounding Poem
Rounding Whole Numbers Round 474 to the closest hundred. 474 Find your number Look right next door Four or less, just ignore Five or more, add one more 474 Rounded to the hundreds becomes 500
470 Round 474 to the closest 10’s 474 Find your number Look right next door Just ignore 470
What about decimal numbers The same rules (and poem) apply! Round 4.167 to the closest hundredths 4.167 Find your number Look right next door 5 or more, add 1 more 4.17
Round 42.73 to the closest tenth If you are asked to round to the nearest tenth…….your answer stops at the tenth place! Example: Round 42.73 to the closest tenth would be 42.7
Special Case! Rounding a 9 Round 2.197 to the hundredths Since there is a “9” in the hundredths place consider the tenth and hundredths together 19 now look next door do you leave it at 19 or move it to 20? 20 because 7 is 5 or more 2.20
4.95 rounded to the nearest tenth is 5.0 Round 4.95 to the closest tenth Since there is a “9” in the tenth spot consider the ones and tenths together…… should you leave it at 49 or move it to 50? 4.95 rounded to the nearest tenth is 5.0
Let’s Watch a Quick Video for more information http://www.watchknowlearn.org/Video.aspx?VideoID=56895&CategoryID=836
You try…. Round to tenths: Round to hundredths: 4.56 4.6 18.784 18.78 5.32 5.3 9.46 9.456 10.00 0.98 1.0 9.997
Least Common Multiple You should already know how to find the least common multiple, but let’s do a quick review.
1. Multiple The product of 2 or more whole numbers. 4: 4, 8, 12, 16, 20, 24, 28 We sometimes call this skip counting or counting by 4. 4x1 4x2 4x3 4x4 4x5 4x6 4x7
12 and 24 are common multiples of 4 and 6 When a number is a multiple of two or more numbers 4: 4, 8, 12, 16, 20, 24, 28 6: 6, 12, 18, 24, 30, 36, 42 12 and 24 are common multiples of 4 and 6
3. Least Common Multiple (LCM) The least number greater than 0, that is a multiple of two or more numbers. 4: 4, 8, 12, 16, 20, 24, 28 6: 6, 12, 18, 24, 30, 36, 42 12 is the smallest (least) number both 4 and 6 have in common, so it is the least common multiple.
Do you remember how we use the least common multiple with fractions? The least common denominator is the same as the least common multiple of the two denominators. I’m going to show you an easier way than the list method to find the LCM/LCD of two numbers.
This method is referred to as the “cake method” or the “ladder method”. As our denominators get larger, it can become more difficult to use the list method to find the LCM/LCD. Step 1 Step 2
Step 3 Step 4
Step 5 Step 6
Let’s Watch a Quick Video for more examples https://www.youtube.com/watch?v=b6qehkDuioQ
You Try…… Find the LCM/LCD 1) LCM/LCD is 24 2) LCM/LCD is 120
Shoulder Partner Practice Use the ladder method to find the LCD in your notebook. We will review the answers as a class.
Homework