If you're not good at mental addition, check into this problem set and become a master before you check out! Each page includes an inspiring slogan! Current exams only feature problems with aligned digits, so working through this problem set will help you concentrate. If you often lose track of what you're calculating, skip numbers (forget to include them), always make mistakes when adding (or subtracting) certain numbers, or often misread numbers (mistaking 69 for 96, or entering 740 instead of 704), subtract in the tens place but add in the ones place, or struggle with borrowing from 10,000 or 5,000, this is a very common issue. This is the best material for you. I recommend copying the problems without writing on them, and practicing repeatedly until you completely memorize them. B5 size (with answer key) If you only purchase this item, it will be sent in simple packaging (waterproof only) via non-standard mail. Regular mail is cheap, but if your mailbox is small, it may be folded to fit. If your mailbox can't accommodate B5 size, or if you need anonymous shipping, you can upgrade to Nekopos for an additional 30 yen, so please comment. Abacus materials are not subject to price reductions. Discounts may be available if you purchase multiple items and save on shipping, but due to copyright issues, they will not be sold below the list price. #SoronyanAbacusMaterials ← You can see all the abacus materials here. Please read the profile carefully! Read carefully! Read carefully! Then, if you have no questions or need to combine orders, please purchase without commenting. Weakness Overcome Abacus materials Mental addition Mitorizan Mitirizan Mental addition Elderly Brain training Right brain Right brain activation Preventing aging