( 1) 1 + 7 + 9 =

(2) 18 - 9 - 4=

(3) 15 - 7 - 6=

(4) 15 - 3 - 8=

(5)8 + 1 + 8 =

(6) 17 - 15 - 1=

(7)2 + 7 + 5 =

(8) 1 1 - 6 - 1=

(9) 1 1 - 6 - 1=?

Teaching objectives:

1. Make students understand the meaning of addition and subtraction, master the operation order and calculate correctly.

2. Initially cultivate students' observation ability and language expression ability of looking at pictures continuously.

3. Make students experience the close relationship between mathematics and life through teaching, and cultivate students' interest in learning mathematics.

Teaching emphasis: Correct calculation of continuous addition and continuous subtraction.

Teaching process:

First, check the import:

1. Oral calculation: addition and subtraction within 10.

The whole class drives the train and does oral calculations.

2. Look at the table calculation. Download the demonstration courseware "The Significance of Addition and Subtraction"

How many chickens are eating rice? How many chickens are coming? How many chickens are there in Qiu Yi? How to calculate in the form of columns?

Show:

Why do you want to add? (A * * * is required. How many chickens are there? Three chickens that eat rice and two chickens that come again should be counted together, so it is calculated by addition. )

How many chickens are eating rice now? How many are left? How much is left? How to calculate in the form of columns?

Show:

Why use subtraction? (Only a few chickens are required, so the remaining two chickens are removed from the whole five, so subtraction is used for calculation. )

Students have a good grasp of the meaning of addition and subtraction, and today we will apply it to further learn new knowledge.