Journalist Marcelo López Chavez published a math challenge on El Comercio testing readers' speed and logical reasoning with an eight-second countdown.
The combined operation requires solvers to calculate 240 divided by the quantity 18 minus 6, plus 35 multiplied by 2. Participants are tasked with finding the correct total of 90 before the eight-second timer expires.
The puzzle is intended for readers who want to test their arithmetic skills, either individually or by competing alongside friends and family members.
Step by step PEMDAS solution
López Chavez explained that completing the equation under time pressure requires applying the PEMDAS rule. The acronym defines the standard order of operations in mathematics: parentheses, exponents, multiplication, division, addition, and subtraction.
To reach the correct result, solvers must first perform the subtraction inside the parentheses, subtracting 6 from 18 to get 12. Next, 240 is divided by 12, which produces 20.
The third step involves multiplying 35 by 2 to obtain 70. Finally, adding 20 and 70 yields the definitive answer of 90.
Cognitive benefits of mental exercises
Mental health experts cited by the publication noted that brain teasers provide helpful temporary entertainment that activates cognitive functions while clearing immediate worries.
The experts stated that solving math challenges enhances mental processing speed, strengthens logical reasoning, elevates focus, and teaches individuals to handle errors with greater persistence.
They added that regular practice with numerical puzzles drives analytical thinking and assists people in working through everyday problems.
Additional puzzles and author background
López Chavez encouraged readers seeking to improve their mental agility to practice daily and explore further math exercises available through El Comercio.
The publication also highlighted a separate combined operation challenge, asking participants to solve 50 minus the quantity 16 plus 8 divided by 4 multiplied by 3 plus 2 within a seven-second limit.
López Chavez studied journalism at Universidad Jaime Bausate y Meza and possesses two years of experience in digital media. He works as a real-time writer for Mag, an entertainment and lifestyle section of the Peruvian newspaper El Comercio based in Lima.
