About Soroban Expertise I have a systematic and orderly way to organize the facts in a word problem, which (usually) leads clearly to the necessary equation. I think I can help with all types of word problems.
Experience 38 years of teaching college-level math, mostly at a two-year college.
Education/Credentials BS and MS in mathematics, SUNY Albany
Expert: Soroban Date: 2/15/2008 Subject: algebra systems of equations word problem
Question My daughter is having difficulty with system of equations word problems like this: The ten's digit of a two-digit number is 1 more than 4 times the units' digit. If 63 is subtracted from the number, the order of the digits is reversed. find the number.
Answer Hello, Lili!
These can be tricky if you don't understand
how two-digit numbers are constructed.
Let T = tens-digit
and U = unit-digit
The two-digit number is: 10T + U (Do you see why?)
"The tens-digit is 1 more than 4 times the unit-digit."
This translates to: T = 4U + 1 --> T - 4U = 1 [1]
"If 63 is subtracted, the order of the digits is reversed."
This translates to: 10T + U - 63 = 10U + T
which simplifies to: 9T - 9U = 63 --> T - U = 7 [2]
