El Comercio real-time writer Marcelo López Chavez has issued a brain-training math challenge requiring participants to solve a combined operation in nine seconds.
The equation, 315÷(28−7)+(16+14)4, tests numerical reasoning speed by asking solvers to calculate the exact answer under a strict time limit.
Solving the exercise depends on performing arithmetic steps in a precise sequence. Solvers must first subtract seven from 28 inside the first parentheses to obtain 21. Next, adding 16 and 14 inside the second parentheses gives 30.
Continuing the calculation, dividing 315 by 21 produces 15. Solvers then multiply 30 by four to get 120. Adding 15 and 120 yields the final result of 135.
Order of Operations Rule
López Chavez noted that applying the PEMDAS rule is essential for completing the problem within the target timeframe. The acronym establishes the proper sequence for arithmetic operations: Parentheses, Exponents, Multiplication, Division, Addition, and Subtraction.
In standard mathematics, order of operations rules ensure that numerical expressions resolve to a single correct value. Operations within parentheses take priority, followed by exponentiation, multiplication and division, and finally addition and subtraction.
Brain Stimulation and Age Adaptation
Timed arithmetic tasks serve to stimulate brain function and test mental agility during leisure moments. López Chavez said inviting friends or family members to attempt the puzzle offers a way to compare cognitive performance under time pressure.
The author explained that mathematical exercises suit individuals of all ages when adapted to cognitive development levels. In early childhood education, instructors use modeling, thinking aloud, visual representations, and task breakdown into smaller steps. For adults, the difficulty of numerical tasks can be increased.
Related Mathematical Speed Tests
The publication included several additional numerical challenges for readers testing their calculation speed. One problem asks solvers to calculate 96÷(18-6)+14x3 within an 11-second limit.
A second exercise requires solving 360−(96÷12)(18+7) in eight seconds, a speed benchmark associated with exceptional reasoning skills. Another equation, (18x9)6+36÷6, also carries an eight-second deadline.
Author and Publication Background
Marcelo López Chavez studied journalism at Jaime Bausate y Meza University and has two years of digital media experience. He currently works as a real-time writer for the Mag section of Peruvian newspaper El Comercio, which is headquartered in Pueblo Libre, Lima.
