Two Olympiad Mathematics Problems in Grade Five of Primary School (Beijing 16 1 Training Center Primary School)
1, because the least common multiple of 8, 10 and 12 is 120, 120-7= 1 13, so the answer is13.
2. Subtract the extra amount from the total, so that there are 27-3=24 pencil cases, 38-2=36 pens, 43- 1=42 pencils, and the greatest common divisor of 24, 36 and 42 is 6, so each class can get 24/6=4 respectively.