Fiftyfine _ Minute _ Math

15 Minute Math This presentation will review different math skills that will help you with every day math problems Each lesson takes approximately 15 minutes to Almost anyone can find an extra 15 minutes out of his or her day, whether it be during breakfast or right before bed In just under weeks, you can review all the TABE Computation Math sections Look for the Professor He has special hints to help make working the math problems faster and easier 15 Minute Math    Decimals o Lesson – What Are Decimals? o Lesson – Addition & Subtraction o Lesson – Multiplication o Lesson – Division Fractions o Lesson – What Are Fractions? o Lesson - Addition & Subtraction (no whole #s) o Lesson – Addition & Subtraction (with whole #s) o Lesson – Multiplication & Division Percentages o Lesson – Converting Decimals to Fractions to Percents o Lesson 10 – Calculating the Part o Lesson 11 – Cross-Multiplication Method     Integers o Lesson 12 – Addition & Subtraction o Lesson 13 – Multiplication, Division, & Absolute Value Algebra o Lesson 14 – Adding & Subtracting Variables o Lesson 15 – Multiplying & Dividing Variables o Lesson 16 – Square Roots Order of Operations o Lesson 17 – Please Excuse My Dear Aunt Sally o Lesson 18 – Order of Operations with Variables Practice Tests o Lesson 19 – Practice Test #1 o Lesson 20 – Practice Test #2 15 Minute Math – Decimals Lesson # – What Are Decimals? This lesson explains how to read and work with decimals Problem: You work in a medical lab and you need to tell your coworker how much medicine you need “I need two tenths of a gram of insulin.” Saying numbers correctly can ensure everyone is talking about the same thing 15 Minute Math – Decimals Lesson # – What Are Decimals?  Decimals are numbers that are less than but greater than 0 < 0.1 < (0.1 is between and 1, so it is a decimal)  They appear to the right of the decimal point whole number decimal 39.1 “39” is the whole number part “.1” is the decimal part  “39.1” is read… “Thirty-nine and one tenth”  “0.1” is the same thing as “.1” “.1” is just a lazy way of writing the number 15 Minute Math – Decimals te nth ou th sa ou nd sa s nd hu s nd re ds te ns on es te nt hs hu nd re dt th h ou sa s nd te nth ths ou sa nd th s Lesson # – What Are Decimals? 10,000 + 2,000 + 300 + 40 + + + 07 + 008 + 0009 The “3” is in the hundreds column,  Remember, so there are “3 hundreds” decimals have a If all the other numbers were “th” at the end of a 0, then the number would be their names 00300.0000, which is 300 (three hundred.) The “7” is in the hundredths column, so there are “7 hundredths.” If every other number were a 0, then the number would be 00000.0700, which is 0.07 (seven hundredths.) de de 4) c ci im Sa m th y al al e th pa po la e r in st co t t, nu lu sa m mn y be n “a r am nd is ” e w he re 15 Minute Math – Decimals Re e th ad th e yo u e 3) W 2) 1) Re ad he r th e w ho le To read a number… se e nu m be r pa rt Lesson # – What Are Decimals? For example: 20.045 is read, “Twenty and forty-five thousandths.” s th nd sa hs ou dt th re nd hu ths n te  Extra zeroes to the far right of a decimal don’t change the value, but they change how you pronounce the number 0.2 = 0.20 = 0.200 but… 0.2 = “two tenths” 0.20 = “twenty hundredths” 0.200 = “two hundred 15 Minute Math – Decimals Lesson # – What Are Decimals? Try it yourself What numbers are these? Three and two hundredths = 3.02 Forty and two thousandth = Twelve and twelve hundredths = Eighty and eighty ten-thousands = How you say these numbers? 37.03 = Thirty-seven and three hundredths 9.04 = 20.040 = 100.01 = Which of these are true: A) 2.01 = 2.010 C) 2.001 = 2.100 E) 2.10 = 2.100 End of Lesson B) 2.01 = 2.001 D) 2.10 = 2.010 F) 2.0010 = 2.001 Click for answers: Forty and two thousandth = 40.002 Twelve and twelve hundredths = 12.12 Eighty and eighty ten-thousands = 80.0080 9.04 = nine and four hundredths 20.040 = twenty and forty thousands 100.01 = one hundred and one hundredth 15 Minute Math – Decimals Lesson # – Addition & Subtraction 15 Minute Math – Decimals Lesson # – Addition & Subtraction   Line up the decimals points Put zeroes in the blank spaces to help you see what you’re adding 24.3 + 18.45  24.30 +18.45 42.75 18.62 – 3.8  18.62 / - 3.80 14.82  When adding, don’t forget to carry when numbers add up to more than 10  When subtracting, don’t forget to borrow if the top number is smaller than the bottom number 15 Minute Math – Decimals Lesson # – Addition & Subtraction  All numbers have a decimal point, even if you can’t see it For example, $15 can also be written as $15.00 99 91 /// // 20 + 4.02  20.00 + 4.02 24.02 100 – 25.783 Remember when you’re borrowing, you can’t borrow from nothing (zero) Make sure you borrow all the way over to the first non-zero number you  100.000 - 25.783 74.217  Even if you don’t see the decimal point, it’s actually at the end 100 = 100 = 100.00 15 Minute Math – Decimals Lesson # – Addition & Subtraction Try it yourself 2.89 + 1.5 = 20.6 + 10.9 = 3.13 + = 20 + 8.2 = 9.373 + 3.34 = + 2.8 = 12.99 – 8.1 = 19 – 3.2 = 2.933 – 1.2 = 8.4 – 5.555 = 20 – 2.5 = 100 – 2.66 = End of Lesson Click for answers: 2.89 + 1.5 = 4.39 20 + 8.2 = 28.2 12.99 – 8.1 = 4.89 1.733 20.6 + 10.9 = 31.5 9.373 + 3.34 = 12.713 19 – 3.2 = 15.8 3.13 + = 12.13 + 2.8 = 11.8 2.933 – 1.2 = 15 Minute Math – Decimals Lesson # – Multiplication 15 Minute Math – Decimals Lesson # – Multiplication   Don’t worry about the decimal until you’re done multiplying everything First multiply, and then count up the places to the right of the decimal point and put the decimal in the answer 3.51 x 1.4  351 ×14 1404 decimal +3510 4914 places      4.914 So, 3.51 x 1.4 = 4.914! first, multiply 351 by then, multiply 351 by 10 then, add up the numbers last, since there are a total of decimal places in the problem, start from the right and move the decimal places to the left in the answer (the problem has decimal places and so does the answer) 15 Minute Math – Decimals Lesson # – Multiplication  Remember to only count numbers to the RIGHT of the decimal point 2.3 × 0.0002  23 ×2 46  0.00046 decimal places decimal places So, 2.3 x 0.0002 = 0.00046!  Sometimes you may see 00046 instead of 0.00046 Both are right, but it’s more common to put a in the ones place 15 Minute Math – Decimals Lesson # – Multiplication  There are some shortcuts you can take if you’re multiplying by a multiple of 10 Multiples of 10 are things like 10, 100, 1000 and also things like 0.1, 0.01, 0.001, etc shift the decimal left places (if you (don’t see the decimal point it’s at the end) 297 × 0.0001 = 0.0297 decimal places move the decimal point right spaces (100 has 0’s) 2.309 × 100 = 230.9 Try not to think about if you’re moving the decimal to the right or the left Think if you need to make the number larger (because you’re multiplying by a number bigger than 1) or if you need to make the number smaller (because you’re multiplying by a number between and 1) Then move the decimal point in the direction that will make the number bigger 15 Minute Math – Decimals Lesson # – Multiplication Try it yourself 27.2 × 9.2 = 3.2904 × 0.22 = 62.5 × 12.8 = 38 × 0.25 = 0.034 × 0.026 = 8.02 × 2.1 = 2.04 × 0.001 = 589 × 100 = 10.2 × 1.2 = 0.34 × 0.5 = 5.89 × 100 = 9.9999 × 0.01 = End of Lesson Click for answers: 27.2 × 9.2 = 250.24 38 × 0.25 = 9.5 2.04 × 0.001 = 0.00204 0.34 × 0.5 = 0.17 3.2904 × 0.22 = 0.723888 62.5 × 12.8 = 800 0.034 × 0.026 = 0.000884 8.02 × 2.1 = 16.842 589 × 100 = 58,900 10.2 × 1.2 = 12.24 5.89 × 100 = 589 9.9999 × 0.01 = 15 Minute Math – Decimals Lesson # – Division 15 Minute Math – Decimals Lesson # – Division  Remind yourself of the steps you need to take when dividing 8203 Divide 21|172263 21|172263 Multiply 21|172263 -168 Subtract 21|172263 -168 Bring down one more number and it again 21|172263 -168 42 -168 42 -42 06 - 63 -63 15 Minute Math – Decimals Lesson # – Division Step - Move the decimal of the divisor (outside the house) as far to the right as you can Step - Move the decimal of the dividend (inside the house) by the same number of spaces Step - Move the decimal straight up onto the answer line Step - Divide like normal Problem 8.91 ÷ 3.3 Steps & Step  33 |89.1 Step 2.7  33 |89.1  3.3 |8.91  33 |89.1 - 66  Think of the division sign, | , like a house With all 231 division problems, the first number goes inside the - 231 house (the 8.91) and the second goes outside the house (3.3)  If you forget, think about a problem you know 10 ÷ 15 Minute Math – Decimals Lesson # – Division Problem Steps & 8.91 ÷ 0.33  0.33 |8.91  33 |891 Step  33 |891 Move the decimal places to the right Problem Steps & Step Step 27  33 |891 - 66 231 - 231 Step 2700 8.91 ÷ 0.0033 0.0033 |8.91  33 |89100  33 |89100  33 |89100 - 66 Move the decimal places to the right 231 Fill in the empty spaces with zeroes - 231 15 Minute Math – Decimals Lesson # – Division Try it yourself 3.2 ÷ 64 = 60.8 ÷ 19 = 187.53 ÷ = 3.2 ÷ 6.4 = 60.8 ÷ 0.19 = 187.53 ÷ 0.03 = 32 ÷ 6.4 = 0.608 ÷ 0.19 = 18753 ÷ 0.3 = 32 ÷ 0.00064 = 608 ÷ 1.9 = 0.0018753 ÷ 0.3 = End of Lesson Click for answers: 3.2 ÷ 64 = 0.05 60.8 ÷ 19 = 3.2 187.53 ÷ = 62.51 3.2 ÷ 6.4 = 0.5 60.8 ÷ 0.19 = 320 0.03 = 6251 32 ÷ 6.4 = 0.608 ÷ 0.19 = 3.2 187.53 ÷ 18753 ÷ 0.3 ... and forty thousands 100.01 = one hundred and one hundredth 15 Minute Math – Decimals Lesson # – Addition & Subtraction 15 Minute Math – Decimals Lesson # – Addition & Subtraction   Line up... 12.713 19 – 3.2 = 15.8 3.13 + = 12.13 + 2.8 = 11.8 2.933 – 1.2 = 15 Minute Math – Decimals Lesson # – Multiplication 15 Minute Math – Decimals Lesson # – Multiplication   Don’t worry about the... × 100 = 58,900 10.2 × 1.2 = 12.24 5.89 × 100 = 589 9.9999 × 0.01 = 15 Minute Math – Decimals Lesson # – Division 15 Minute Math – Decimals Lesson # – Division  Remind yourself of the steps you