(no subject)

[tinyjo]

So, if we're going to buy expensive schemes to teach children maths, can the providers please make sure that the activities make sense and aren't, you know, wrong or anything.

Say the number: four thousand, seven hundred and eighty-three. Ask children in their groups to write this in figures. Write it on the board to check: 4783. What is the lowest number you can add so that all four digits change? Allow 3 or 4 minutes to try this, then take feedback. (1111 is the lowest number that can be added so that all four digits change, making 5894.) Will this always be the lowest number? Can you find a 4-digit number where all four digits can be changed by adding a lower number? Ask children to explore this, starting by finding different types of number (e.g. multiples of 10 or 100) where a lower number can be added. Ask them to write some general rules (e.g. if the number ends in 9, then the lowest number that can be added to make all four digits change is 1101.)

Just.... No, don't do that! I can't even think of an interpretation that might make that make sense.

Comments

[tea-and-cuddles.livejournal.com]

It doesn't work.

For example, 8889 ends in 9, none of the other digits is a 9, and the lowest number you can add to change all four digits is 111, which is lower than 1101.

[phlebas.livejournal.com]

Indeed. But I presume the idea is that you start from the obvious mal-rule from 'what if it ends in a 9', come up with counterexamples, refine the rule accordingly and hope they end up with a better grasp of how it really works. It's a questionable approach to teaching maths (being a rough application of the scientific method) but not completely nonsensical.