The missing number is 1,620. The digits in the tens places (green in the figure below) of the numbers in columns 1, 2, 4 and 5 are added together. The total value is represented by the digits in the ...

Find the missing number puzzles serve as an invaluable tool for enhancing the cognitive abilities of students and school-going kids. These puzzles require critical thinking, problem-solving skills, ...

Students in Melissa Williams' kindergarten class at the Westminster School in Atlanta, Georgia, practice connecting quantities to written numbers — a key part of number sense. Credit: Holly Korbey for ...