15 + 12+ 25 + 35 +42 + 25 = (15 + 25 + 35 + 25) + (12 + 42) = 100 + 54 = 154
=(15+35)+(25+25)+(12+42)
=50+50+54
=154
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=?
15 + 25 = ?
20 + 30 = ?
25 + 35 = ?
Tính:
a/ 48 + 25 – 38 = 73 – 38 = 35
b/ 100 - 38 + 15 = 62 + 15 = 77
15 + 16 + 19 = ?
25 + 35 + 45 = ?
5 – 10 + 15 – 20 + 25 -30 + 35 – 40 + 45 – 50 + 55
Tính:
a) 6 kg + 20 kg =
b) 35 kg – 25 kg =
c) 16 lít + 5 lít =
d) 35 lít – 12 lít =
giúp mình giải toán lớp 2 : Tính nhanh
a) 12+24+35-2-14-25
b) 1-2+3-4+5-6+7-8+9
c) 25-12-3+24+36
Tìm x :
a./ x-15=20
b./ 35-x=25
tính nhanh
5 - 10 + 15 - 20 + 25 - 30 + 35 - 40 + 45 - 50 + 55
