Our next unit is on multiplication and division. We MUST learn our multiplication facts! We learn about factors and multiples initially. We discuss, using 1 inch tiles, that some numbers of tiles can be made only one way. For instance, three tiles can only make a 1X3 array(rectangle). Three is prime. Other numbers of tiles can be fashioned several ways. Four tiles can be made into a 1 by 4, or a 2 by 2 array. Four is not prime,but rather is composite. Skip counting may help students learn multiples of some numbers. Soon we will be learning to do "long" division. One digit into three digits, and for the brave among us, 2 digits into 3 digits. We always check our work by multiplying our answer(quotient) by the divisor. Our answer should be equal to the dividend. Don't forget to add the remainder!!! Some of us have learned how to find the square roots of non square numbers. try the square root of 205 (hint: what squares are on either side of 205? 14²= 196 15²=225 How far away is 205 from 196 compared to 225. It is about 3/10(9/29) of the way from 196 to 225. So our answer will be about. 14.3 Cool! We did this without a calculator.
Learning square numbers is helpful for those students proficient in math concepts. 1X1=1 2X2=4 3X3=9 etc. I will teach some students how to determine squares of larger numbers without actually doing the 2by2 digit multiplication. There are some very interesting "tricks" to do with squares regarding 2 digit multiplying. Oh, so much fun, and so little time!!! Mr. G.
There are many math activities that will help your child in math this year, and the years to follow. Many of these things can be done in the car on the way to practice, or on the way to grandma's house.
*Work on multiplication facts using flash cards. I have them if students ask.
* Practice skip counting... 3,6,9,12 up and down...33,30,27,24
* Do mental math(no pencil and paper). Say: " 4 plus 3... minus 2...plus 5...minus 3 equals what?" This will help students "hold" numbers in their mind's clipboard.
* play counting games. Throw 3 to 5 dice and find the sum as fast as possible.
* start with a determined amount of pennies in your hand(10). Show some of them and have student say how many are still in fist.
*find the prime factors of a number. Remember prime factor trees? 40
8 X 5
4X2 X 5
^ | | 2X2 X2 X 5= 2³ • 5
* Have students demonstrate understanding of 2 digit X 2 digit multiplication.
* Some students are getting long division. Divide, Mult., Subt., Check and Bring down.
Does McDonalds Sell Cheeseburgers? This helps us remember what to do.
* Have student explain divisibility rules. How do you know a number goes into another number evenly? What will the remainder be? If its even, 2 goes in evenly etc.
Start figuring out percentages of simple fractions. 1/2 =50% =.50 1/3= 33 1/3%=.333
1/4=25%=.25 1/8= 1/2 of 25%= 12 1/2 %=.125 1/6= 1/2 of 33 1/3%= 16 2/3% =.167
- Geometry- names of shapes, how to catagorize triangles, and quadrilaterals. Figure the area and perimeters of triangles and quads. Measure angles and label as acute, obtuse, or right. How many lines of symmetry does a certain shape have? What will a certain shape look like when given a 90, or 180 degree turn?(rotational symmetry) What will a certain shape look like if flipped?(reflectional symmetry) When are two shapes congruent?(same size AND shape) Or similar?(same shape and proportion, not size) We have wonderful math dictionaries for students(and parents) to check out that explain many of the items we will cover in the next month.
We will be studying division and multilication with larger numbers. You may see homework coming home that asks students to multiply a 3-digit number by a 2-digit number in more than one way. Most students know the standard algorithm(the way we adults were taught to do it!) but may benefit by trying other ways. The old F.O.I.L. method is just one way.