速算:
8
3
7
3 + 5 =
5-2 =
10-3 =
8-5 =
3
8
3
9
3 + 2 +3 =
10-5-2 =
3 + 2 +4 =
7-2-3 =
2
现在还有几只天鹅?
4 + 3-2
4 + 3-2 =
5
你是怎么算出的?
4 + 3-2 =
7
5
5
从左往右计算
与连加、连减一样!
2
5
5
4- 2 + 3 =
5
4+3-5=
①
②
③
④
8-2-2=
3-2+4=
2+3+2=
2
4+3 -5=
①
②
③
④
8-2-2=
3-2+4=
2+3+2=
5
7
4+3-5=
①
②
③
④
8-2-2=
3-2+4=
2+3+2
5
2
现在还有几只天鹅 来自淘豆网m.daumloan.com转载请标明出处.
