Forgive the lack of effect in my voice, the screen capture thing and video uploader was being annoying so I had to make/upload the video several times.
More speed math tutorials?
If I see people are watching my videos through the statistics google offers I'll add more tutorials like 3 or 4 digit multiplication.
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Click on one of the addition or multiplication text title's. It'll make the intro disappear. From there it says "Type 1 to Start".
Options
@i1Speed Math Options Automiss Off/On: Will automatically count the question as missed once your time expires. This is the only reason for having missed in the stats. Restart Level: Restarts the level. Hide Time: Hide the timer below the submit box. Hide Meter: Hide the moving blue bar under the submit box. Savestar On/Off: Your stars reflect your best time only. If off, your stars will be reevaluated per turn.
The arrows near the slowest and best time are to move slowest, best, and record times down or up. The Q is to organize by questions so you can check if you started slowing down or speeding up, and by how much.
Quick Keys
Clicking "e" in the submit box will restart the level and start the timer.
Part 1: Introduction, Adding 2- and 3-digit numbers Part 2: Adding 2- and 3-digit numbers, Calculating tips, Subtracting 2- and 3-digit numbers Part 3: Subtracting 2- and 3-digit numbers Part 4: Subtracting 2- and 3-digit numbers, Multiplying 2- and 3-digit numbers by 1-digit numbers Part 5: Multiplying 3-digit numbers by 1-digit numbers, Percentages, Division of 2- and 3-digit numbers by 1-digit numbers Part 6: Division of 3-digit numbers by 1-digit numbers Part 7: Multiplying fractions Part 8: Multiplying, Adding and subtracting fractions, Converting fractions to decimals Part 9: Converting fractions to decimals, Estimation, Squaring Part 10: Squaring, Algebra Part 11: Algebra, Fibonacci addition trick
Speed addition
To add rapidly start from left to right.
Step 1: Add the first two numbers. Step 2: Glance if the next pair of numbers is greater than one, if it is, add one to the first pair, and write the remainder for the second pair. If it's less than zero just add straight down Step 3: Repeat step 2 until you run out of numbers.
Speed Multiplication
Double Digits
Step 1: Multiply the first two numbers together. Step 2: Cross multiply and add the Sums. Step 3: Multiply the last two digits. Step 4: Add the sums of each step.
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Speed Math Tricks
The following tips are taken from the book "Rapid Math Tricks and Tips" (c) 1992 by Edward H. Julius. The tips themselves are public domain and the author's direct explanation or examples are not used. This is not the full list of tricks. Mistakes listed here do not reflect the author of the book.
Multiply by .4, 4,40,400 etc
Simply double the number twice and adjust the decimal, because 2x2=4
Multiply by .8, 8, 80, 800 etc
Double it three times, because 8 is 2 x 2 x 2
Multiply by .5, 5, 50, 500 etc
Divide by two and adjust decimals, because 5=10/2
Square two digit numbers ending in 5
Multiply the tens digit by a whole number, then attach 25 to the end.
Multiply two digit numbers by .11, 11, 110, etc
Add the two digits your multiplying by 11 together and put their sum in the middle of the same two digits. 12*11=?, 1+2=3,solution 132
Multiply by .25,25,250, etc
Divide by four, and adjust the decimal. Because 2.5=10/4.
Divide by .25,25,250, etc
Multiply times 4 and adjust the decimal.
Multiply a one or two digit number by .99,99,990
Substract the number by one and call it value 1, then substract the number from 100 and call it value 2. Put the two values together.
Multiply a two digit number times .101,101,1010
Write the number twice and adjust the decimal. 64*101=6464
Rapidly Multiply .125,1.25 12.5 etc
Divide by 8, adjust decimals. Because 5/4 or (10/8) is 1.25.
Rapidly Divide .125,1.25 12.5 etc
Multiply 8, adjust decimals. Because 5/4 or (10/8) is 1.25.
Multiply by .9, 90, 900 etc
Multiply the value your multiplying times nine, time 10 instead. Take that solution and substract the value your multiplying times nine from it. 9 x 21, we say 10 x 21 =210-21=answer.
Rapidly Multiply by .12, 1.2, 12, 120 etc
Multiply times 10 and call it value 1, multiply times 2 and call it value 2. Add the solutions. 12 * 60= (10x60)600+(60*2)120
Multiply by 15
Multiply by 10 and get value 1, divide by 2 then multiply by 10 and get value two. 15*34 = (10x34)340+((34/2)*10)170
Educational
