Help students recognise when a mental strategy is more efficient than a vertical algorithm with these mental strategies vs algorithm slides for subtraction. Students learn to use friendly numbers, like subtracting 100 instead of 99 then adding 1 back, to solve problems mentally, compare this to using the algorithm for more complex calculations, then practise choosing and applying the most efficient method.
What's included:
Introductory slides explaining mental strategies using friendly numbers
Worked examples solving mentally, using the algorithm, and identifying which method is more efficient for a given problem
10 example and practice slides in total, including Your Turn problems where students choose and apply their own method