Tính nhanh: P = ⅔ - ¼ + 5/11
______________
5/12 + 1 - 7/11
Tính nhanh: 2/3-1/4+5/11/5/12+1-7/11
Tính nhanh:
P = (2/3 - 1/4 + 5/11) / (5/12 + 1 - 7/11)
1/ Tính nhanh:
a. 5/7×5/11+5/11×2/9-5/7×17/11
b. 1×2+2×4+3×6+4×8+5×10/3×4+6×8+9×12+12×16+15×20
coi lại câu a
1.1+1.1+1.1+1.1+1.1/1.1+1.1+9.3+6.8+.2
TÍNH NHANH:
2/3-1/4+5/11
5/12+1-7/11
Đặt \(A=\frac{\frac{2}{3}-\frac{1}{4}+\frac{5}{11}}{\frac{5}{12}+1-\frac{7}{11}}\)
\(A=\frac{\frac{44}{132}-\frac{33}{132}+\frac{60}{132}}{\frac{55}{132}+\frac{132}{132}-\frac{84}{132}}\)=\(\frac{\frac{44.1}{132}+-\frac{33.1}{132}+\frac{60.1}{132}}{\frac{55.1}{132}+\frac{132.1}{132}-\frac{84.1}{132}}\)
\(A=\frac{\frac{1}{132}.\left(44-33+60\right)}{\frac{1}{132}.\left(55+132-84\right)}\)=\(\frac{\frac{1}{132}.71}{\frac{1}{132}.103}\)
\(A=\frac{71}{103}\)
bạn ấy sai chỗ quy đồng buoc hai ý phải là 88/132
Tính nhanh:
P = \(\dfrac{\dfrac{2}{3}-\dfrac{1}{4}+\dfrac{5}{11}}{\dfrac{5}{12}+1-\dfrac{7}{11}}\)
P=(2/3 -1/4+5/11):(5/12+1-7/11)
P=(88/132-33/132+60/132):(55/132+132/132-84/132)
P=115/132:103/132
P=115/103
1+2+3+4+5+6+7+8+9+10+11+12+13-1-2-3-4-5-6-7-8-9-10-11-12
tính nhanh
1+2+3+4+5+6+7+8+9+10+11+12+13-1-2-3-4-5-6-7-8-9-10-11-12
=(1-1)+(2-2)+(3-3)+(4-4)+(5-5)+(6-6)+(7-7)+(8-8)+(9-9)+(10-10)+(11-11)+(12-12)+13
= 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 0 + 13
= 13
1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 - 1 - 2 - 3 - 4 - 5 - 6 - 7- 8 - 9 - 10
= (1+12) + (2+11) + (3+10) + ( 4+9) + (5+8) + (6+7) + 13 - (1+11) - ( 2+10) - ( 3+9) - (4+8) - (5+7) + 6 + 12
= 13 * 7 - 12 * 6 + 6
= 13
Ai k mk mk k lại
đừng quy đồng rồi tính
TÍNH NHANH:
2/3-1/4+5/11
5/12+1-7/11
Tính nhanh: P=(2/3-1/4+5/11)/(5/12+1-7/11)
Đặt A=2/3-1/4+5/11
A=5/12+5/11
A=115/132
Đặt B=5/12+1-7/11
B=103/132
Suy ra:P=A/B
P=115/132:103/132
P=115/103
Tính nhanh
2/3 - 1/4 +5/11
P=---------------------
5/12 +1 - 7/11
nhanh mik tick
7 Tính nhanh tổng sau
A=(2+3+4+5+6+7+8+9+10+11+12+13)-(1+2+3+4+5+6+7+8+9+10+11+12)
A=(2+3+...+13)-(1+2+...+12)=2+3+...+13-1-2-...-12=(13-1)+(2-2)+(3-3)+...+(12-12)=12