This is a typical elementary school math application problem. First of all, we need to know what this problem requires, and we need to examine this problem carefully. How much is a jigsaw puzzle? Mom bought four puzzles with 28 yuan, so the price of one pair should be 28 divided by 4 equals 7. So every pair of 7 yuan.

Mathematics can be a tool to improve children's IQ quickly, effectively and comprehensively. Mathematics learning plays an important role in developing ideas. Children's thinking ability is the core of intelligence. If the child is in primary school, his thinking ability has been fully exercised. Then there will be no stumbling on his future math road.