Numbers questions This is a list of recently added questions about numbers. Play numbers quiz and see all the questions. Which numeral system was in use in ancient Sumer and Babilon?Sexagesimal. Remnants of highly composite sexagesimal system are in use even today for measuring angles, geographic coordinates and especially time. An hour of time is divided into 60 minutes, which in turn are divided into 60 seconds. Created by: smyruvery hard 32% octaloctal2027binarybinary1841decimaldecimal2429sexagesimalsexagesimal3020mathematics riddles » How many players of one team are there in a pool during the water polo game?7. A team consists of 6 field players and one goalkeeper in the water at any one time. Created by: Paweł Kołodziejczykhard 53% 551644772598994441111194water riddles » Which of the following is true for the solution with the pH=0?The OH − ion concentration is smaller than the H+ ion concentration. In chemistry, pH is a numeric scale used to specify the acidity or alkalinity of an aqueous solution. It is the negative of the logarithm to base 10 of the activity of the hydrogen ion .Traditionally the pH is being defined as: pH = - log10 [H+], where [H+] it is a H+ ions concentration in mol/dm^3 (M). So if pH = 0 this H+ ions concentration is 1 mol/dm^3 and the solution is strongly acidic.Created by: Paweł Kołodziejczykvery hard 25% the OH − ion concentration is smaller than the H+ ion concentrationthe OH − ion concentration is smaller than the H+ ion concentration560the OH − ion concentration is greater than the H+ ion concentrationthe OH − ion concentration is greater than the H+ ion concentration431the OH − ion concentration is equal of the H+ ion concentrationthe OH − ion concentration is equal of the H+ ion concentration590Such solution doesn't existSuch solution doesn't exist582chemistry riddles » What is the volume of a soap bubble with radius R=1 cm?4/3π cm3. Equation for the volume of a sphere: 4/3πR^3.Created by: Paweł Kołodziejczykhard 58% 3/4π cm33/4π cm316004/3π cm34/3π cm347174,3π cm34,3π cm3847It isn't possible to calculateIt isn't possible to calculate952geometry riddles » What is the result of 2+2*2?6. The multiplication has a priority over addition, and so the result is 2+(2*2) = 2+4 = 6.Created by: Paweł Kołodziejczykvery easy 83% 44123881012666681Not enough dataNot enough data192mathematics riddles » Which of the following numbers is the greatest?1/3. Quite surprisingly, most players answer that both answers 1/3 and 33% are correct. But 1/3 is more than 33%. (it is 33.3333333...)Created by: globalquiz.orghard 53% 1/31/360640,30,350233%33%1091Both answers 1/3 and 33% are correctBoth answers 1/3 and 33% are correct3636mathematics riddles » Which number is considered unlucky in East Asia?4. Words "four" and "Death" have very similar pronunciation in Chinese, Vietnamese, Korean and Japanese. In East Asia many buildings do not have a 4th floor. Some high-rise residential buildings omit all floor numbers with "4", e.g., 4, 14, 24, 34 and all 40–49 floors. Created by: Sumit Tamanghard 50% 331435443397121215124040406South Korea riddles » Which of the following is a prime number?16769023. A prime number has no positive divisors other than 1 and itself. Hence, a prime bigger than 2 cannot be even. All prime numbers bigger than 5, written in the usual decimal system, end in 1, 3, 7, or 9. Created by: Sumit Tamangaverage 66% 23882990238829901059167690231676902378063837729638377296100111723835117238351847math riddles » Which of the following Roman numerals stands for 4?Both IV and IIII. Both notations are correct and historically Roman numerals were often written less consistently than today. The notation 'IIII' is often seen on clock faces. The reason for that may be practical, to avoid confusing the IV and VI when the clock is held upside down (although other theories also exist).Created by: globalquiz.orgvery hard 28% IVIV2521IIIIIIII44Both IV and IIIIBoth IV and IIII1062None of the aboveNone of the above58ancient Rome riddles » Which pH number describes a substance that is neither acidic nor alkaline?PH 7. Solutions with a pH value below 7.0 are considered acidic, whereas solutions with pH values above 7.0 are basic.Created by: Cleoeasy 70% pH 0pH 01970pH 7pH 77218pH 10pH 10429pH 0.5pH 0.5608chemistry riddles » Play mathematics quiz and see all the questions.