Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

You are not logged in.

- Topics: Active | Unanswered

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Okay.

69. p1+c2+p3...+c100=?

70. Is it prime?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Okay.

71. p47 - p46

72. p38 / p27

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

Hi;

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

73. p2^2

74. add the digits of #73

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.** **A number by itself is useful, but it is far more useful to know how accurate or certain that number is.**

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Correct!

# 75 squared

# 76 cubed

# 77 (sum of digits of #75) cubed

# 78 (sum of #76 and #77) raise to the fifth power

# 79 (sum of digits of #78) squared

# 80 Is (sum of digits of #75-79) prime?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

# 81. to the four

# 82. prime?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

Can you explain these a bit? I do not understand the questions.

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Okay. I'm sorry, but:

#81. What is 81^4?

#82. Is (Sum of digits of 81^4) prime?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

I mean sum of digits, like 4+3+0+4+6+7+2+1. Anyways, nice try!

I'll write the items more user friendly.

83. What is 3 to the 5?

84. Multiply that answer by itself.

85. Multiply it by the nth prime (let n be the answer to #83).

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

I missed the sum part, sorry. The question you asked in the last post was clear enough, thanks.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

Hi;

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

Please hide your answers bobbym or you will receive an infraction.

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

Sorry, latex error.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

It's okay. Time to sharpen our minds!

#86. 1+2+4+8+1+6+3+2+6+4+1+2+8...+1+0+4+8+5+7+6

#87. 1+3+9+2+7+8+1+2+4+3+7+2+9...+3+8+7+4+2+0+4+8+9

#88. 1+5+2+5+1+2+5+6+2+5+3+1+2+5...+9+7+6+5+6+2+5

Note: Give me the pattern first before the sum. Both in separate posts.

#89. Sum of digits of #86-88.

After solving for the sum of 86, 87 and 88, respectively, answer this in a separate post, again.

*Last edited by mathaholic (2014-05-18 14:02:41)*

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

Hi;

I do not understand the questions please explain.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

*Last edited by ShivamS (2014-05-28 01:27:46)*

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Hmm, since I'm too lazy to check...

#90. What is the square root of 121?

#91. It's obvious that it's prime. But, does the sum of its digits equal a prime number, too?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

Offline

**mathaholic****Member**- From: Earth
- Registered: 2012-11-29
- Posts: 3,246

Whoops, I forgot to specify:

#91. Does the sum of the digits of the answer in #90 prime?

Mathaholic | 10th most active poster | Maker of the 350,000th post | Person | rrr's classmate

Offline

**ShivamS****Member**- Registered: 2011-02-07
- Posts: 3,648

Offline

**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 103,823

Hi;

Should be #92

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**

Offline