724 +63 + 276 + 27=

2079+ 186+ 921 =

13579 +5468+ 523+421=

45 + 28 + 55 + 72=

2548+ 642 +452 =

14 + 187 + 86+213 =

45+178 + 622+ 155 =

234 + 462 + 66 + 38 =

583 +999+ 417=

512+7485+ 515 + 48= 

do la tinh bang cach thuan tien nhat nhe 

tong cua hai so chan  lien tiep la so chan lon nhat co 3 chu so .

Vay so chan be la :           

So chan  lon la :

cac ban giup minh duoc khong 

3 phut 15 giay =................. giay

9 tan 25 kg = ............... kg 

1/6 ngay =.............. gio 

75 000 g = ............... kg 

3phut 15 giay = .................. giay 

21 000 kg = .......................... kg 

4tan 5 kg = .................... kg 

3 gio 15 phut = ........................... phut

tinh gia tri bieu thuc a+b x5 ,voi a = 123456 va b =175 .