Qingdao Edition Fourth Grade Mathematics Volume 2

Description

"Taishan Ancient Trees" PPT courseware

1. Situation introduction

Red Gate: 3449 trees

Zhongtianmen: 527 trees

Nantianmen: 1640 trees

How many ancient trees are there in Hongmen, Zhongtianshan and Nantianmen?

Dai Temple: 250 trees

Lingyan Temple: 10891 trees

How many times the number of ancient trees in Lingyan Temple is that in Dai Temple?

Based on this information, what questions can you ask?

What mathematical information do you know from the picture?

2. Cooperation and exploration

How many ancient trees are there in Hongmen, Zhongtianshan and Nantianmen?

3449 + 527 + 1640 = ? (tree)

When the number in the formula is relatively large and it is troublesome to calculate, we can use a calculator to calculate it.

Do you know a calculator?

Questions for group exploration

1. Tell me what you know about calculators.

2. What are the external characteristics, basic structure and basic functions of a calculator?

3. What are the functions and operation methods of the main keys of the calculator?

Steps to use a calculator:

Turn on the phone and press the ON/OFF button.

Press the 3 4 4 9 keys in sequence.

Press the + key.

Press the 5 2 7 keys.

Press the + key.

Press the 1 6 4 0 keys in sequence.

Press the = key to display the results.

To clear the screen, press the C key; to turn off the phone, press the ON/OFF key.

Activity 1: Try calculations

765＋469＝ 589×76＝

3208－2965＝625÷25＝

6848-579+386＝

Activity 2:

First group:

17+83＝ 62-12= 1000×5＝

Second Group:

7865+3497＝ 835×23= 1305÷45＝

Requirements: (1) All boys must calculate the first set of questions orally or with writing.

(2) All girls use calculators to calculate the second set of questions.

give it a try

For the following two sets of questions, what calculation method is more appropriate? Give it a try.

The first group: 17+83＝ 125×8＝ 1000÷5＝

The second group: 7865+3497＝ 835×23＝ 1305÷45＝

By using a calculator to calculate the above two questions, what do you think are the advantages of using a calculator to calculate?

3449+527+1640=5616 (tree)

10891÷250= 43.564

Can you use a calculator to calculate the following two questions?

545 + 285 -139 =

816÷68×27＝

For two-step calculation questions of the same level, press the keys directly to calculate the result from left to right according to the order of operations.

3. Independent practice

1. A faucet that is not closed tightly will drip about 18 kilograms of water every day, and this water will be drained away in vain...

◆According to this calculation, a faucet that is not closed tightly will waste ( ) kilograms for two years (calculated as 365 days in a year).

◆Put the water in drinking water barrels (each barrel is calculated as 15 kilograms). The water can fill approximately ( ) barrels.

◆If a family of three uses 6 barrels of water every month, this water is enough for ( ) months, which is about ( ) years.

2. Use a calculator to calculate.

559+241= 721－324=

59×84= 3123÷9=

729+362-826= 667+234×12=

5846-(1428+519)= (1645-865)×29=

(545+285)÷5= 3661÷7+245=

summary

In practical applications, we should use the calculator reasonably according to actual needs. We should not rely too much on the calculator for calculations, but should use it in practical applications.

The evolution of computing tools

In primitive societies, humans had low intelligence. At that time, they put stones into leather bags or strung shells into beads, and used the "one-to-one correspondence" method to calculate the items that needed to be counted.

Later, people invented knotting long ropes to record things or count, which was much more convenient than using stones and shells.

About six or seven hundred years ago, the Chinese invented the abacus, which combined the decimal counting method and a set of calculation formulas and is still in use today. It is regarded by many as the earliest digital computer.

Keywords: Taishan Ancient Tree Teaching Courseware, Qingdao Edition Fourth Grade Mathematics PPT Courseware Download, Fourth Grade Mathematics Slide Courseware Download, Taishan Ancient Tree PPT Courseware Download, .PPT format;

For more information about the "Taishan Ancient Trees" PPT courseware, please click the "Taishan Ancient Trees" ppt tab.

"Taishan Ancient Trees" PPT courseware 2:

"Taishan Ancient Trees" PPT courseware 2 1. Situation introduction Hongmen: 3449 trees Zhongtianmen: 527 trees Nantianmen: 1640 trees How many ancient trees are there in Hongmen, Zhongtianshan and Nantianmen? Dai Temple: 250 trees Lingyan Temple: 10891 trees. The number of ancient trees in Lingyan Temple is several times that of Dai Temple..

File Info

Update Time: 2024-11-11

This template belongs to Mathematics courseware Qingdao Edition Fourth Grade Mathematics Volume 2 industry PPT template

Preview