BÀI BÁO CÁO KHOA HỌC TẠI BẮC KINH ATCM 2009 THE SCIENTIFIC REPORT IN BEIJING - CHINA

The 14
th
ASIAN TECHNOLOGY
CONFERENCE IN MATHEMATICS,
BEIJING, CHINA 2009
BEIJING NORMAL UNIVERSITY
December 17-21, 2009
THE MINH TRAN
HCMC UNIVERSITY OF TECHNOLOGY
VIETNAM
TITLE : USING SCIENTIFIC
CALCULATORS TO SOLVE
MATHEMATICAL PROBLEMS
Authors : THE MINH TRAN
DEPARTMENT OF APPLIED MATHEMATICS
HCMC UNIVERSITY OF TECHNOLOGY (HCMUT)
VIETNAM
Introduction
•
Using a calculator is an important skill for
students. As they grow and progress through
their education.
•
They will learn advanced math skills that
certainly require them to use a calculator .
•
A few quick steps can help anyone use the
device and solve mathematical problems .
•
I have organized exams : “Excellent students use
scientific calculators to solve mathematical

problems ”
Therefore, I have built math-calculator subject
and technology in mathematics
WE CAN USE SCIENTIFIC
CALCULATORS :
1.VIETNAM CALCULATOR
VN- 570RS
3.CASIO FX-570MS
4.CASIO FX-570ES2.TEXAS INSTRUMENTS
83 Plus
A. ARITHMETIC
•
We calculate : 3281978 × 8791803
•
We input 3281978 × 8791803 on the screen
•
Press the = key. Answer : 2.885450403
•
We know that answer have 14 digits but the digit 3 can
have rounded
•
We delete the digit 3 at the first number and the digit 8 at
the second number then we multiply two numbers together
•
Press the = key. Answer : 2.232710263
We continue to delete the digit 2 at the first number and the
digit 7 at the second number then we multiply 81978 and
91803 to get 7525826334
•
Result : 3281978 × 8791803 = 28854504026334

Note : when you multiply two numbers, you need to
thoroughly check digits
13
10
×
1.Multiply two numbers
11
10×
2. Find x, know that :
•
We input 381978 ÷ 382007 on the screen
•
Press the = key. Answer : 0.999924085
•
We continue to press : × 3 - 8 then we press 9 times the
= key. The final result have saved to the Ans key
•
Now,we have then we press : Ans - 1 =
Result : x = - 1.11963298
3
8

3
8

3
8

3
8


3
8

3
8

3
8

3
8

3
8

1
1

x

381978
382007

1
−
x
x
Ans
+

=
1
1
1−
x
3. Find a natural number n , know that the
number contains the first four digits and the
end four digits are digit 1
Step 1 : Find the number contains the end four digits are digit 1.
Solution :
The number contains the end digit is digit 1
The number contains the end two digits are digit 1
The number contains the end three digits are digit 1
The number contains the end four digits are digit 1
Answer : the number contains the end four digits are
digit 1
n1 = 8471
3
n
3
1
3
71
3
471
3
8471
3
8471
Step 2 : Find the number contains the first four

digits are digit 1.
Solution :
We have ( we get the number 223 )
We try ( answer contains two digit
are digit 1 ) . we do not choose the number 223
The number contains the first two digit are digit 1
We have ( we get the number 480 )
We try ( answer contains four digits
are digit 1 )
We choose the number 480 . Answer : n2 = 480
If we do not find n2, we can calculate
to find n2
Result : n = 4808471 and
193
10...1216.12238471 ×=
7.480111101111
3
=
203
10...11178.14808471
=
...11111000111;1111001111
33
14.22311111111
3
=
3
22308471
3
4808471 1111. . .1111

=
4. Find natural number x,y, know that :
( and y include a digit)
Solution : we guess : x is digit 2 or 3
● When x = 2 : (we do not choose x = 2 )
● We choose the digit 3 , we have :
( )
2
2 2
5 541 1 ( )4481448( )
x
y y y x x y=
2
x
4 4
(5 ) 59 12117361y
≤ =
9 9
9
5410109448144809 5 541 1 94481448 9 5419199448144899y y y y
≤ = ≤
55,99303467 5 56, 00348007 6y y
⇔ ≤ ≤ ⇒ =

Result : x = 3 , y = 6 and 5416169448144896
Furthermore , we can find y by the SOLVE key.We input
( )
9
13 12 11 10 9 2
50 541 10 10 1 10 10 9 10 4481448 10 90y y y y

+ = × + × + × + × + × × × + +
on the screen. We press SHIFT SOLVE key and press 1 key
6y
⇒ =
9
56 =