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Dividing by 1/2
To be archived: Math problems at key stage 2 level
By Seraphina Wilkins on Sunday, October 07, 2001 - 06:20 pm:

Dear Nrich,

I have been asked a problem in my math homework 'divide 30 by 1/2 and add ten'.

My Dad says the answer is 70 by the route of asking how many halves there are in 30, 60 + 10 = 70.

But I thought it might be that I should divide 30 by half of itself eg 15, which would = 2 + 10 = 12.

What do you think Nrich?

By the way, I came by your ace site through a Google search.

Seraphina, aged 10

By Jenny Peters on Sunday, October 07, 2001 - 09:14 pm:

I think that your Dad's method is probably the right one.

Divide 30 by a half and add 10

= 30/0.5 + 10
= 70

By Seraphina Wilkins on Monday, October 08, 2001 - 02:35 pm:

Thank you very much.

Seraphina

[Editor: Dividing by 1/2 is the same as multiplying by 2]