don steward
mathematics teaching 10 ~ 16

Friday 19 April 2013

non-calculator multiplication practice

see long multiplication teaching here

a long multiplication puzzle from counton
what are the missing numbers?

[questions: why aren't there three lines in the solution?
what number must the orange triangle be, and why?
what number (other than 1) has the same last digit when it is squared?
why must the yellow circle be the purple circle + 1? ]

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