MENGKUADRATKAN DI LUAR KEPALA BILANGAN YANG ANGKA SATUANNYA 5
Kalikan angka puluhannya dengan angka puluhan yang satu lebih besar dari angka puluhan tersebut . Hasilnya merupakan angka ratusan dari perkalian itu. Lalu tambahkan 25 kepadanya.
Contoh :
252 = ( 2 X 3 ) 100 + 25 = 600 + 25 = 625.
552 = ( 5 X 6 ) 100 + 25 = 3000 + 25 = 3025.
9952 = ( 99 X 100 ) 100 + 25 = 990000 + 25 = 990025.
Ini dapat dijelaskan sebagai berikut :
( 10x + 5 )2 = 100x2 + 2 X 10x X 5 + 25
= 100x2 + 100x + 25
= ( x2 + x ) 100 + 25
= x ( x + 1 ) 100 + 25
Sumber : Ruseffendi . 1982 . Dasar – dasar Matematika Modern . Bandung : Penerbit Tarsito .
Tentang marinazahara22
Oke 1st I'll introduce my self, My real name's MARINA ZAHARA. But more people especially my friends called and know me as Rina, sometimes Ena.My NIM : 06022681318023.I borned in Prabumulih at March 23, 1991.
Right now I'm 22 years old. In my family I'm the first, I have one brother and one sister. My parents name are Zaherman and Malasari. I love my family so much.
My hobby is playing badminton, reading novel, listening to the music, and browsing on internet.
Wise words : prayer gives strength to the weak, making people you who do not believe to believe, and give courage to those who fear.
My Basic Education :
1. TK Nurrohman Lahat ( 1996 - 1997 )
2. SD Negeri 46 Lahat ( 1997 - 2003 )
3. SMP Negeri 5 Lahat (2003 - 2006 )
4. SMA Negeri 2 Lahat ( 2006 - 2009 )
5. UNSRI Mathematics Education Study Program ( 2009 - 2013 )
6. UNSRI Megister Mathematics Education ( 2013 - Now )
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