1) 12 + 23 + 34 - 53
2) ( 3x - 24 ).74=2.75
3) Tien muon cat 1 tam bia hinh chu nhat co kich thuoc 72cm va 96cm thanh nhung manh nho nhu hinh vuong bang nhau sao cho tam bia duoc cat het. Tinh do dai lon nhat cua canh hinh vuong .Khi do cat duoc may hinh vuong?
4) Tren tia Ox lay 2 diem A va B sao cho OA=2cm ; OB=6cm
a) Tinh do dai doan thang AB
b) Lay I la trung diem cua doan thang AB. Tinh do dai doan thang OI
c) Chung to A la trung diem cua doan thang OI
5) Tinh tong :
A= 2015 + 2015.2 + 2015.3 + 2015.4 +... + 2015.99 + 2015.100
giup mik di cac ban iu dau