tinh nhanh: 4+7+10+13+....+58+61
tinh nhanh
12/7 x 4/13 +12/14 x 14/26 -6/7 x 2/13
1 tim x
Ai nhanh to k
x x - 4/7 = 15/20
x x 2/7 -2/3 =1/2
x : 5/4 + 4/5 =2
2 tinh
4/3 x 7/8 x 5
8/9 x 6/5 x 2/3
4/7 : 5/7 x 10/11
8/13 : 7/13 : 4
1+2+3+4++5+6+7+8+9+10+11+12+13+14++15+16+17+18+19+20
Hoi tong tren bang bao nhieu (tinh nhanh va giai thich cach lam)
13/4 + 3/4 x 8=
13/7 - 5 : 10/3=
giúp em nhanh ạ thứ 2 tuần sau e thi ạ
tinh tong cac so chia het cho 4
tinh nhanh
3 cong 8 cong 13 cong ...cong 48
1 cong 3 cong 5 cong 7 cong ...2021
a 7/15 + 4/5 b 2/3 - 3/8 c 4/7 x 21/16 : 5/8 13 x 42 x 11/ 33x 26 x 35 tinh bang cach nhanh nhat sos x2 giup minh voi
Exercise 13
b) (1 + 4 + 7 + ... + 61) - ( 3 + 6 + 9 + ... +60)
tinh nhanh 1/4*3+1/4*5+1/6*5+1/7*6+1/8*7+1/9*8+1/10*9=