194-(3*x-9*17)=30-24/3
194-(3*x-9*17)=22
3*x-9*17=194-22
3*x-9*17=171
3*x=171+9*17
3*x=171+153
3*x=324
x=324/3
x=108
Vậy x=108
Tìm x, biết:
a) x + 39 = 51 + 17
b) 41– x = 24 – 9
c) x – 33 = 19 + 10
d) x + 30 = 74 – 32
123 x X = 615
8 + 8 + 8 = 24
17 + 8 = 25
17 - 8 = 9
24 + 25 + 9 = ?
Tính nhẩm:
9 : 3 = ..... 6 : 3 = .....
3 : 3 = ..... 15 : 3 = .....
12 : 3 = ..... 21 : 3 = .....
18 : 3 = ..... 24 : 3 = .....
27 : 3 = ..... 30 : 3 = .....
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26+27+28+29+30+31+32+33+34+35+36+37+38+39+40+41+42+43+44+45+46+47+48+49+50+51+52+53+54+56+57+58+59+60+61+62+63+64+65+66+67+68+69+70=?
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20+21+22+23+24+25+26
28+27+26+25+24+23+22+21+20+19+18+17+16+15+14+13+12+11+10+9+8+7+6+5+4+3+2+1+=....................................................?
hãy tính nhanh:
A.1+2+3+4+5+6+7+8+9+10+11+12+13-14=?
B.30-29+28-27+26-25+24-23+22-21...+12-11+10-9+8-7+6-5+4-3+2-1=?
Tìm x (theo mẫu)
Mẫu:
x + 3 = 9
x = 9 - 3
x = 6
a) x + 8
b) x + 5 = 17
c) 2 + x = 12
d) 2 + x = 12
e) x + 4 = 15
Tính nhẩm:
3 x 4 = ............... 3 x 5 = ...............
4 x 7 = ............... 5 x 4 = ...............
15 : 3 = .............. 24 : 4 = ..............
5 x 6 = ............... 5 x 9 = ...............
25 : 5 = ..............