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# no calculator

1. ### 111,111 x 111,111 no calculator

Solve this with no calculator. From left to right, count from 1 to 5 Then write 6 Then count down from 5 to 1 12,345,654,321

3. ### Multiply two-digits numbers by 11 shortcut

53 x 11 Write 3 as the right most digit in 53 3 5 + 3 = 8. Write that to the left of 3 83 Then write the 5 as the left most digit 583 35 x 11 Write 5 as the right most digit in 35 5 3 + 5 = 8. Write that to the left of 5 85 Then write the 3 as the left most digit 385 57 x 11 Write the 7 in 57...
4. ### Multiply by 49 No Calculator Shortcut

we start at the top and write 4 and add 5 for every line we go down: 49 * 1 = 4 49 * 2 = 9 49 * 3 = 14 49 * 4 = 19 49 * 5 = 24 49 * 6 = 29 49 * 7 = 34 49 * 8 = 39 49 * 9 = 44 49 * 10 = 49 Next, we start the bottom of the list. add on a 0 at the end, and for each line we go up, we add 1 more...
5. ### Find the last digit of 2 raised to the 2020 no calculator

Check out this pattern: 2^1= 2 2^2= 4 2^3 = 8 2^4= 16 2^5 = 32 2^6 = 64 2^7 = 128 2^8 = 256 The last digit repeats itself in blocks of 4 2, 4, 8, 6 We want to know what is the largest number in 1, 2, 3, 4 that divides 2020 without a remainder. LEt's start with 4 and work backwards. 2020/4 =...
6. ### Multiply by 39 No Calculator Shortcut

we start at the top and write 3 and add 4 for every line we go down: 39 * 1 = 3 39 * 2 = 7 39 * 3 = 11 39 * 4 = 15 39 * 5 = 19 39 * 6 = 23 39 * 7 = 27 39 * 8 = 31 39 * 9 = 35 39 * 10 = 39 Next, we start the bottom of the list. add on a 0 at the end, and for each line we go up, we add 1 more...
7. ### (98)^2 no calculator mental math

Round 98 to the nearest 10. This is 100. Call this a. Calculate b which is a - our original number: b = 100 - 98 b = 2 We can use this formula: (a - b)^2 = a(a- 2b) + b^2 Given a = 100 and b = 2, we have: (100 - 2)^2 = 100(100 - 2(2)) + 2^2 98^2 = 100(96) + 4 98^2 = 9600 + 4 98^2 = 9,604
8. ### Multiply Even Numbers by 5 No Calculator Shortcut

Take the number being multiplied by 5. Divide it in half Add a zero 14 * 5 Divide 14/2 = 7 Add a 0 --> 70
9. ### Simplify log(4) + log(12)

Answer Choices A) log(3) B) log(48) C) 16 D) log(8) E) log(16) We know that log(ab) = log(a) = log(b) Looking at our problem, we see that a = 4 and b = 12, so we have: log(4) + log(12) = log(4 * 12) log(4) + log(12) = log(48) Answer B

11. ### Multiply by 29 No Calculator Shortcut

we start at the top and write 2 and add 3 for every line we go down: 29 * 1 = 2 29 * 2 = 5 29 * 3 = 8 29 * 4 = 11 29 * 5 = 14 29 * 6 = 17 29 * 7 = 20 29 * 8 = 23 29 * 9 = 26 29 * 10 = 29 Next, we start the bottom of the list. add on a 0 at the end, and for each line we go up, we add 1 more from...
12. ### Multiply by 19 no calculator shortcut

we start at the top and write 1 and add 2 for every line we go down: 19 * 1 = 1 19 * 2 = 3 19 * 3 = 5 19 * 4 = 7 19 * 5 = 9 19 * 6 = 11 19 * 7 = 13 19 * 8 = 15 19 * 9 = 17 19 * 10 = 19 Next, we start the bottom of the list. add on a 0 at the end, and for each line we go up, we add 1 more from...
13. ### 98^2 no calculator FOIL

98 = 100 - 2 (100 - 2)(100 - 2) Using FOIL: 100^2 - 100(2) - 100(2) + -2^2 10000 - 400 + 4 9604
14. ### Vice Versa Percentage Method

x% of y is the same as y% of x Example 1: 18% of 10 is the same as 10% of 18 10% is easy because we move the decimal one place left to get 1.8 Example 2: 40% of 50 is the same as 50% of 40 50% is easy because we cut a number in half 40/2 = 20

16. ### Find the last digit of 4^2081 no calculator

Find the last digit of 4^2081 no calculator 4^1= 4 4^2 = 16 4^3 = 64 4^4 = 256 4^5 = 1024 4^6 = 4096 Notice this pattern alternates between odd exponent powers with the result ending in 4 and even exponent powers with the result ending in 6. Since 2081 is odd, the answer is 4.
17. ### Find the greatest common factor without a calculator

Find the greatest common factor without a calculator Check out this table stacking method and the product of factors.
18. ### Finding a 20% tip no calculator

Finding a 20% tip no calculator We have 2 methods to calculate a 20% tip. Divide by 5 Shift one decimal place left and take the value. Multiply by 2 Example: 180 tip, find a 20% tip: Method 1: 180/5 = 36 Method 2: Move decimal place left = 18 Multiply this value by 2: 18 * 2 = 36
19. ### Subtracting 9s shortcut

Subtracting 9s shortcut Add the digits of the larger number 10 - 9 = 1 + 0 = 1 11 - 9 = 1 + 1 = 2 12 - 9 = 1 + 2 = 3 13 - 9 = 1 + 3 = 4 14 - 9 = 1 + 4= 5 15 - 9=. 1 + 5 = 6 16 - 9 = 1 + 6= 7 17 - 9= 1 + 7 = 8 18 - 9 = 1 + 8 = 9 19 - 9 = 1 + 9 = 10
20. ### (Sqrt(24) + sqrt(96))/2

(Sqrt(24) + sqrt(96))/2 Simplify sqrt(24) 24 = 6 * 4 where 4 is the perfect square sqrt(24) = 2 * sqrt(6) Simplify sqrt(96) 96 = 16 * 6 where 16 is the perfect square sqrt(96) = 4 * sqrt(6) Simplified, we have: (2 * sqrt(6) + 4 * sqrt(6))/2 6 * sqrt(6)/2 3 * sqrt(6)