B
ài 2
:
Tính b
ằ
ng cách thu
ậ
n ti
ệ
n
:
7408
+ 2863 + 1592 + 137
304
7 + 1456 + 1000
+
69
53
–
456
.
.............................................................................................................................
.
............
.............................................................................................................................
..............
.........................................................................................................
.
.................................
.....................................................................
......................................................................
Bài
3
:
Vi
ế
t s
ố
th
ích h
ợ
p
v
ào
ô tr
ố
ng
T
ổ
ng c
ủ
a
hai s
ố
100
13
5
2009
Hi
ệ
u c
ủ
a hai s
ố
20
65
1945
S
ố
l
ớ
n
S
ố
b
é
B
ài 4:
Đ
àn g
à c
ó 120 con g
à m
ái v
à g
à
tr
ố
ng, s
ố
g
à m
ái nhi
ề
u h
ơn s
ố
g
à tr
ố
ng l
à
30 con. T
ìm s
ố
g
à m
ái,
s
ố
g
à tr
ố
ng c
ủ
a
đ
àn g
à
đ
ó
T
óm t
ắ
t
................................................................
................................................................
.............
...................................................
................................................................
................................................................
B
ài gi
ả
i
................................................................
................................................................
.............
...................................................
................................................................
................................................................
................................................................
.............
...................................................
B
ài 5
:
M
ộ
t
t
ấ
m b
ìa
h
ình
ch
ữ
nh
ậ
t c
ó
n
ử
a
ch
u vi l
à
30c
m
. Chi
ề
u d
ài h
ơn chi
ề
u r
ộ
ng
20 cm. T
ính di
ệ
n t
ích t
ấ
m b
ìa
đ
ó
T
óm t
ắ
t
................................................................
................................................................
.............
...................................................
................................................................
................................................................
B
ài gi
ả
i
................................................................
................................................................
.............
...................................................
................................................................
................................................................
................................................................
.............
...................................................
.......................................
.................
........
B
ài 6
:
T
ính nhanh
1
+ 3 + 5 + 7 +
9 + 21
+ 23 + 25 + 27 +
29
.
.............................................................................................................................
.
............
.............................................................................................................................
..............
.........................................................................................................
.
.................................
.....................................................................
......................................................................