This is a gentle math problem collection from America. It's a math workbook and answer key/teacher's guide for 6th graders. There are 180 problems, including geometry problems, calculation problems, probability problems, and logical thinking problems (the classification is shown in the last photo). I obtained this over a decade ago to help science students improve their English conversation skills. I used it to practice reading simple math problems in English and explaining them in English. It's a spare book that I never used, and it has been stored on the bookshelf as is. There are no markings, but there is some aging. Student edition: 22cm x 10cm. Teacher's edition: 35cm x 21.5cm. The teacher's guide is large, so I will loosely roll it up and ship it in a box.