March 19th - March 23
*Read (at least 20 mins a night)and record (parents should write the title of the book their child is reading, as well as the number of minutes read, so Dojo points can be awarded)
* Report cards go home on Tuesday
* School closes at 11:30 for parent-teacher interviews
*Teacher in service on Friday - No school for students
* Breakfast Club Monday- Thursday
* Recycling Blitz on Fridays
* Field trip to Fluvarium -Postponed until May 25th
* Students should be reviewing math strategies - We worked on the subtraction of two digit and three digit numbers this week .
Here are few examples of how we teach addition, subtraction and estimating.
Estimating Sums
When you do not need an exact answer, you estimate.
When you estimate a sum, you predict a number that is close to the number you would get by adding.
Kaori and Brian are rolling nickels their class collected for a charity.
Kaori counted 59 nickels.
Brian counted 23 nickels.
About how many nickels did they roll altogether?
Estimate to predict the sum: 59 + 23
➤
Kaori adds only the digits in the tens place.
59 has 5 tens.
23 has 2 tens.
Add the tens: 5 tens + 2 tens = 7 tens, or 70
This is front end estimating.
Kaori estimates they rolled about 70 nickels.
➤
Brian takes each number to the closest 10.
59 is closest to 60.
23 is closest to 20.
Add: 60 + 20= 80
Brian estimates they rolled about 80 nickels.
➤
Gemma takes one number to the closest 10.
59 is closest to 60.
Add: 60 + 23= 83
Gemma estimates they rolled about 83 nickels.
There are many ways to estimate a sum.
Adding 2-Digit Numbers
Estimate to predict the answer.
➤
There are 45 dogs in the animal shelter.
There are 37 cats at the same shelter.
How many cats and dogs are there in the shelter?
( Rounding One Number)
Find: 45 + 37
37 is about 40.
45 + 40 = 85. So, my
estimate is about 85.
( Front End Estimating)
40 + 30 = 70.
I estimate the answer
is about 70.
Here are different strategies children used
to solve the problem. ( Actual)
➤
Hannah uses Base Ten Blocks on a place-value mat
to add 45 + 37.
Show 45 with 4 tens and 5 ones.
Show 37 with 3 tens and 7 ones.
5 ones and 7 ones is 12 ones.
Put 10 ones together to make 10.
Trade 10 ones for 1 ten.
This makes 8 tens and 2 ones (82).
➤
Marissa and Jeremy record 45 and 37 as tens and ones.
They add the tens and ones separately and combine the results.
• Marissa adds from left to right.
Add the tens: 40 + 30
Add the ones: 5 + 7
Add the sums: 70 + 12
• Jeremy adds from right to left.
Add 7 + 5.
Add 30 + 40.
Add 12 + 70.
There are 82 cats and dogs in the
animal shelter.
The answer 82 is close to
the estimates 70 and 85.
You can add 37 + 45 or 45 +37.
Subtraction
500 is the same as 499+1
- 123 - 123
Encourage the students to always make sure their numbers are lined up properly.
Practice with grouping and without grouping. Use pictures of base 10 numbers to help or use a number line or 100 chart.
*Read (at least 20 mins a night)and record (parents should write the title of the book their child is reading, as well as the number of minutes read, so Dojo points can be awarded)
* Report cards go home on Tuesday
* School closes at 11:30 for parent-teacher interviews
*Teacher in service on Friday - No school for students
* Breakfast Club Monday- Thursday
* Recycling Blitz on Fridays
* Field trip to Fluvarium -Postponed until May 25th
* Students should be reviewing math strategies - We worked on the subtraction of two digit and three digit numbers this week .
Here are few examples of how we teach addition, subtraction and estimating.
Estimating Sums
When you do not need an exact answer, you estimate.
When you estimate a sum, you predict a number that is close to the number you would get by adding.
Kaori and Brian are rolling nickels their class collected for a charity.
Kaori counted 59 nickels.
Brian counted 23 nickels.
About how many nickels did they roll altogether?
Estimate to predict the sum: 59 + 23
➤
Kaori adds only the digits in the tens place.
59 has 5 tens.
23 has 2 tens.
Add the tens: 5 tens + 2 tens = 7 tens, or 70
This is front end estimating.
Kaori estimates they rolled about 70 nickels.
➤
Brian takes each number to the closest 10.
59 is closest to 60.
23 is closest to 20.
Add: 60 + 20= 80
Brian estimates they rolled about 80 nickels.
➤
Gemma takes one number to the closest 10.
59 is closest to 60.
Add: 60 + 23= 83
Gemma estimates they rolled about 83 nickels.
There are many ways to estimate a sum.
Adding 2-Digit Numbers
Estimate to predict the answer.
➤
There are 45 dogs in the animal shelter.
There are 37 cats at the same shelter.
How many cats and dogs are there in the shelter?
( Rounding One Number)
Find: 45 + 37
37 is about 40.
45 + 40 = 85. So, my
estimate is about 85.
( Front End Estimating)
40 + 30 = 70.
I estimate the answer
is about 70.
Here are different strategies children used
to solve the problem. ( Actual)
➤
Hannah uses Base Ten Blocks on a place-value mat
to add 45 + 37.
Show 45 with 4 tens and 5 ones.
Show 37 with 3 tens and 7 ones.
5 ones and 7 ones is 12 ones.
Put 10 ones together to make 10.
Trade 10 ones for 1 ten.
This makes 8 tens and 2 ones (82).
➤
Marissa and Jeremy record 45 and 37 as tens and ones.
They add the tens and ones separately and combine the results.
• Marissa adds from left to right.
Add the tens: 40 + 30
Add the ones: 5 + 7
Add the sums: 70 + 12
• Jeremy adds from right to left.
Add 7 + 5.
Add 30 + 40.
Add 12 + 70.
There are 82 cats and dogs in the
animal shelter.
The answer 82 is close to
the estimates 70 and 85.
You can add 37 + 45 or 45 +37.
Subtraction
500 is the same as 499+1
- 123 - 123
Encourage the students to always make sure their numbers are lined up properly.
Practice with grouping and without grouping. Use pictures of base 10 numbers to help or use a number line or 100 chart.