Take a look before the exam.
1
The comparison size must be changed to the same knowledge point.
2
Note that the overload problem must be compared.
three
Solve problems, carefully examine questions, and observe changes in the unit.
I. Unit of length
Through basic knowledge
1
In life, a small number of items can be used (
Millimeter, centimeter, decimeter
) is a unit; Large objects,
Commonly used (
rice
)
Be a unit; Measuring long distances usually uses (
kilometre (km)
) do the unit, kilometer is also called (
public
In)
2
、
1
Have (
10
) cells, the length of each cell (
(to) equal to ...
)
, are all (
1
) mm-hmm
three
、
1
Elephant trunk/whip/used in combination with coins
1
The thickness of coins, rulers, magnetic cards, small buttons and keys is about.
1
millimetre
four
When calculating the length, you can only add and subtract the same length unit.
Tip: When converting the length unit, change the large unit to the small unit and add it to the end of the number.
(How many are there in the relationship?
, just add
several
); Replacing small units with large units is deleted at the end of the number.
(How many are there in the relationship?
, just remove a few.
)。
five
The relationship between length units is: (
The advance rate between every two adjacent length units is
10
)
①
The speed of progress is
10
1
rice
= 10
decimetre
1
decimetre
= 10
centimetre
1
centimetre
= 10
millimetre
10
decimetre
= 1
rice
10
centimetre
= 1
decimetre
10
millimetre
= 1
centimetre
②
The speed of progress is
100
1
rice
= 100
centimetre
1
decimetre
= 100
millimetre
100
centimetre
= 1
rice
100
millimetre
= 1
decimetre
③
The speed of progress is
1000
1
kilometre (km)
= 1000
rice
1
Kilometers (kilometers)
= = 1000
rice
1000
rice
= 1
kilometre (km)
1000
rice
= 1
Kilometers (kilometers)
Second, the quality unit
Through basic knowledge
1
When we express the weight of an object, we usually use (
mass unit
)。 In life, lighter items can
Use (
Scold or fight?
) is a unit; According to the quality of general goods, commonly used (
kilogram
) is a unit; Usually measure the quality of heavy or bulk goods.
Commonly used (
many
) do the unit.
Tip: In the conversion of "tons" and "kilograms", converting tons into kilograms means adding at the end of the number.
three
individual
; Put kilograms.
Convert it into tons and remove it at the end of the figure.
three
individual
2
, the ratio of two adjacent mass units is
1000
sequence
2
unit
Addition and subtraction within 10 thousand
Take a look before the exam.
① Vertical format
(
rule
)
② carry
1
And abdication (3) look at the symbols.
(4) Horizontal number (5) Pay attention to calculation and see what the standard must calculate.
6. When estimating, pay attention to estimate the ten digits to single digits and the hundred digits to ten digits.
Through basic knowledge
1
The minuend is a three-digit continuous abdication subtraction operation step:
①
When the columns are vertical, the same numbers must be aligned;
②
When subtracting, which digit is not reduced enough, the previous digit will be returned.
1
; If the previous one is
, and then return from the previous one.
1
2
Pay attention to the middle when doing the problem.
Because I abdicated one after another, I retired a hundred places.
1
By ten o'clock.
10
After that, I also learned from
Ten-digit retreat
1
while
10
Borrow a seat, so there are only ten left.
nine
, no
10
The sum of two three-digit sums.
：
It may also be three digits.
It could be four digits. )
3. formula.
Negative = negative+difference
Sum = Addendum+Another Addendum
Subtraction = minuend-difference
Appendix = Sum-Another Addendum
Difference = minuend-minuend
sequence
three
unit
quadrilateral
Take a look before the exam.
1
If it is mentioned in the application question that the perimeter of the figure is surrounded by lace, fence and railing, then find the length of lace, fence and railing.
And so on are all about the perimeter of the figure.
2
If the topic mentions that one side of the figure is against the wall, the question is how many fences should be used at least, so write down two possibilities. one
If the figure is long against the wall, then the fence length is one length plus two widths;
The second is the width of the figure against the wall, so the length of the fence is one width plus two lengths.
three
Spelling problem: make a big square from top to bottom and a big rectangle from left to right.
Through basic knowledge
1
, yes
four
Sum of straight edges
four
A closed figure with one corner is called a quadrilateral.
2
、
Characteristics of quadrilateral
There are four straight sides and four corners.
three
、
Characteristics of rectangle
Rectangular has two lengths.
,
Two widths, four right angles and equal sides.
four
、
Characteristics of a square
: Yes.
four
A right angle,
four
The edges are equal.
five
、
Rectangular and square are special parallelograms.
six
、
Characteristics of parallelogram
: ① The opposite sides are equal and the diagonal lines are equal.
② Parallelogram is easy to deform. (Triangle is not easy to deform)
seven
、
The length of a closed figure is its circumference.
eight
, formula
Perimeter of rectangle
=
(Dragon
+
Width)
2
The circumference of a square
=
Side length ×
four
Length of rectangle
=
Zhouchang' ao
2
-Width
The side length of a square
=
Zhouchang' ao
four
Width of rectangle
=
Zhouchang' ao
2
During the period of: during the period of.
sequence
four
unit
Division with remainder
Take a look before the exam.
1
Vertical division with remainder, remainder in horizontal division,
2
Remainder must be less than divisor.
three
The units of remainder and divisor in application problems should be determined according to the answers.
four
At most, we should pay attention to solving problems.
Through basic knowledge
1
The relationship between remainder and divisor: when calculating division with remainder
Remainder must be less than divisor.
2.
In the application of division with remainder
: ① Both quotient and remainder have units;
② The unit names of quotient and remainder may be different.
three
, formula
bonus
=
Divider × quotient+remainder
divisor
=
Dividend quotient-remainder
business
=
Residual dividend
sequence
five
unit
time
minute
second
Take a look before the exam.
Familiar with the conversion between hours, minutes and seconds and the forward speed.
60
Will compare the size relationship between the three. Refer to all the bigger questions in the big book.
Will fill in the appropriate time unit.
Through basic knowledge
1
There is on the clock face
three
Root needles, they are (
hour hand
)、(
minute hand
)、(
assistant
), the fastest of which is (
assistant
), go.
The slowest is (
hour hand
)。
2
There is on the clock face
(
12
)
Numbers,
(
12
)
A big grid,
(
60
)
A small cell; Between every two numbers is
(
1
)
A large grid, that is,
(
five
)
A small box.
three
Walk clockwise
1
cellular phone
(
1
)
Hours; Minute hand walk
1
cellular phone
(
five
)
Minutes, go
1
Little brother is
(
1
)
Minutes; Second hand walking
1
cellular phone
(
five
)
Seconds, go
1
Little brother is
(
1
)
Second.
four
Walk clockwise
1
Big grid, the minute hand just left.
(
1
)
Cycle by cycle, minute by minute.
1
The circle is
(
60
)
Points, that is
(
1
)
Clockwise walking
1
Circle, minute hand
To be completed
(
12
)
Round.
five
Walk for a few minutes.
1
Brother, the second hand just left.
(
1
)
Circle, walk with the second hand.
1
The circle is
(
60
)
That is, a few seconds
(
1
)
Minutes.
six
When the hand turns from one number to the next, it is
(
1
hour
)
. The minute hand moves from one number to the next.
(
five
minute
)
. The second hand counts from a number.
Go to the next number.
(
five
second
)
seven
On the clock face, the hour hand and the minute hand are at right angles: (
three
punctually
)、(
nine
punctually
)。
eight
, formula (The ratio between every two adjacent time units is
60
)
1
time
=60
minute
1
minute
=60
second
half time
=30
minute
60
minute
= 1
time
60
second
= 1
minute
30
minute
=
half time
sequence
six
unit
Multiply multiple numbers by one number.
Take a look before the exam.
1
, oral multiplication
(
Integer ten digits, integer, integer times one digit.
)
2
, estimate
(
Estimate first and then calculate.
)
、
three
, two digits multiplied by one digit carry multiplication, two digits multiplied by one digit carry multiplication, three digits multiplied by one digit continuous carry multiplication, middle or end
Three-digit multiplication and zero-sum one-digit carry multiplication.
Through basic knowledge
1
, estimate
. (
Find the approximate multiple digits first, and then calculate. such as
497
×
seven
≈
3500
)
2
、①
Multiply by any number.
②
1
Anything that is not.
Multiply the numbers of to get the original number.
three
How many are there at the end of the factor
Add a few at the end of the product.
four
Multiply three digits by one digit.
The product may be three or four digits.
five
(About) Application:
(1) if there is "about" in the condition, but there is no "about" in the question, find the exact number. →(=)
(2) There are no conditions, but "about" appears in the question. Find out the approximate figure and use the estimate. →(≈)
(3) Conditions and problems are "approximate", approximate and estimated. →(≈)
sequence
seven
unit
A preliminary understanding of scores
Take a look before the exam.
1
Be sure to capitalize when reading.
2
Compare scores to see if they are the same denominator or numerator.
three
There must be some problems in the application of fractions, so don't miss the answers.
Through basic knowledge
1
、
Divide an object or figure into several parts on average, and take some of them, which is the score of the object or figure.
2
、
The more shares a whole is divided equally, the smaller the number represented by each share.
three
、
①
The numerator is the same, but the fraction with a small denominator is large, and the fraction with a large denominator is small.
②
If the denominators are the same, the fraction with large numerator is large, and the fraction with small numerator is small.
four
、
①
Addition and subtraction of fractions with the same denominator
The denominator remains the same, and it only adds and subtracts with the numerator.
②
1
Subtract from the score:
1
It can be regarded as a fraction with the same numerator and denominator.
sequence
eight
unit
possibility
Take a look before the exam.
1
Correct use of "possibility"
、
"certain"
、
The word "impossible"
2
Can correctly judge the size of the possibility according to the size of the quantity, but also can tell the size of the possibility, so that students have many problems in guessing the quantity;
three
Can cope with the ever-changing practice form, but can't really connect the learned knowledge with real life and old knowledge, that is, comprehensively use knowledge.
Improve cognitive ability;
four
The problem of examining questions must be serious, especially the "hidden" conditions;
Through basic knowledge
1
、
"Impossible and certain" both refer to certain phenomena. "Possibility" refers to an uncertain phenomenon.
2
、
Please use "certain, possible and impossible".
①
It must be:
The sun must rise in the east;
The moon must go around the earth;
The earth must be turning every day;
each
People must be born every day;
People must drink water.
②
Possibility:
It may rain in three days;
Flowers may be fragrant;
It may be windy tomorrow;
There may be an exam next week.
③
Impossible:
The sun cannot rise in the west; The earth can't go around the moon; Carp can't live on land;
I can't have eaten nothing since I was born; It is impossible to build a building in the air; I can't be older than my sister.