Solving Problems Without Paper
Date: 9/1/95 at 19:9:51 From: Megan Lee Mead Subject: working problems in my head My name is Megan Mead. I'm in seventh grade and I'm having trouble when we have to do problems in our head instead of on paper. Do you have some ideas on what will help me?
Date: 9/2/95 at 11:47:11 From: Doctor Ken Subject: Re: working problems in my head Hello! To tell you the truth, I'm actually not all that good at doing numbers in my head either. I have gotten better at it though, and here's what has helped me. I don't try to do the addition and multiplication the way that people learn in school, starting on the right and working toward the left. I actually start on the left and go right. I find it easier because you don't have to remember the numbers in the reverse order you really want them in. For example, if we had 342 + 831, here would be my steps: 342 +831 ---- 11 342 +831 ---- 117 342 +831 ---- 1173 The only weird part is when you have to carry numbers. Then you have to go back and change what you had before: 746 +487 ---- 11 746 +487 ---- 122 746 +487 ---- 1233 I do the same thing for multiplication, but that gets a little more tricky to remember all the steps. Can you figure out how to do that? -Doctor Ken, The Geometry Forum
Search the Dr. Math Library:
Ask Dr. MathTM
© 1994-2015 The Math Forum