800 + 200 + 200 + 300 = 800 + 200
= 1000 + (200 + 300)
= 1000 + 500
= 1500
800 + 200 + 200 + 300 = 800 + 200
= 1000 + (200 + 300)
= 1000 + 500
= 1500
100+100+200+200+300+300+400+400+500+500+600+600+700+700+800+800+900+900+?
Tính nhẩm:
200 : 2 = ?
Nhẩm: 2 trăm : 2 = 1 trăm
Vậy: 200 : 2 = 100
800 : 2 =
300 : 3 =
800 : 4 =
x + 800 = 200 + 800 + 300
100 + 200 + 800 + 300 + 900 + 700
400 + 600 = ???
700 + 300 = ???
200 + 800 = ???
100+ 200+ 30 +300+70+700+800+900: 9 ( tinh nhanh)
Tính nhẩm:
a) 3500 + 200 = ..............
3700 - 200 = ..............
7100 + 800 =..............
7900 - 8000 = ..............
4400 + 300 = ..............
4700 - 3000 = ..............
b) 6000 + 2000 = ..............
8000 - 6000 = ..............
8000 - 2000 = ..............
7000 + 3000 = ..............
10 000 - 7000 = ..............
10 000 - 3000 = ..............
2000 + 8000 = ..............
10 000 - 2000 = ..............
10 000 - 8000 = ..............
200 + 800 - 100 + 100 = ?
100 - 100 + 100 = ?
300 + 300 - 900 + 100 = ?
12 + 12 + 12 + 12 + 12 = ?
nhanh cho tick !
X + 200 = 800 - 200