Choose appropriate written or mental subtraction methods

The ArithmeKit 4.12 from Buzzard Publishing's CanDoMaths series is a resource designed to help students enhance their numerical skills, specifically in subtraction. It encourages pupils to choose the most appropriate method—mental or written—for subtracting numbers. The resource includes a variety of subtraction problems, from simple ones where mental calculations might suffice, to more complex ones that require a formal written method. For instance, subtracting 4003 from 3996 may be easily done in one's head, considering the close proximity of the numbers, while a calculation like 5678 minus 3569 might necessitate a written method to avoid mistakes and ensure accuracy.

Further exercises within the kit challenge students to apply different subtraction strategies such as counting on, rounding, or using formal written methods, and to evaluate which method is the most efficient for a given problem. Additionally, the resource includes activities that promote critical thinking, such as creating their own subtraction problems suited to a particular method, and missing digit problems that require students to use logical reasoning. The kit also sparks discussion, as with the character Coco who suggests that rounding is an efficient mental strategy when subtracting numbers with a 9 in the ones column. Students are tasked with agreeing or disagreeing with Coco's assertion, and using practical resources or jottings to demonstrate their understanding of efficient subtraction methods.