Use place value or adjusting to subtract numbers mentally

The ArithmeKit 5.9 from Buzzard Publishing's CanDoMaths series offers a range of exercises to help Year 5 students enhance their mental arithmetic skills, particularly in subtraction. For example, students are encouraged to mentally subtract numbers such as 598 minus 399, and 297 minus 199, using place value understanding or adjusting strategies. Additionally, they are tasked with subtracting larger numbers, such as 545,000 minus 98,000, by initially subtracting 100,000 and then adjusting the result. This method is also applied to a series of similar problems, like 376,000 minus 99,000, and 436,900 minus 97,000, to reinforce the concept.

The exercises also challenge students to determine when rounding to the nearest 100,000 is most efficient for subtraction, prompting them to explore various calculations and identify the smallest number for which this method is still effective. Further, the kit includes problems that require adding or subtracting small numbers from larger ones, such as 497 minus 400 plus 2, and 297 minus 200 plus 1, to practice mental adjustment. Students are encouraged to create their own calculations that require different strategies, fostering a deeper understanding of mental subtraction methods. The kit concludes with a series of subtraction problems involving larger numbers and negative results, reinforcing the concept of efficient mental subtraction and the importance of place value.