Đây là **Đề thi Violympic – Toán 2 - Vòng 10 vòng cấp trường Năm học 2015 -2016** - Ra ngày 23/12/2015 – Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.Anna scored 18 points in 3 games. What might her scores have been for each of the games?

Đây là **Đề thi Violympic – Toán 2 - Vòng 9 vòng tự luyện Năm học 2015 -2016** - Ra ngày 13/12/2015 – Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.Anna scored 18 points in 3 games. What might her scores have been for each of the games?

Đây là **Đề thi Violympic – Toán 2 - Vòng 7 vòng tự luyện Năm học 2015 -2016** - Ra ngày 30/11/2015 – Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.Anna scored 18 points in 3 games. What might her scores have been for each of the games?

Đây là **Đề thi Violympic – Toán 2 - Vòng 7 vòng tự luyện Năm học 2015 -2016** - Ra ngày 10/11/2015 – Q**uestion 1:** Draw X’s and group them in two ways to illustrate the two ways to multiply. Multiplying in two ways on the number line**Question 2: **For each number line, write the two multiplication sentences that the arrows portray.**Question 3:** Skip-count to fill in the multiplication table of 3. How does the picture relate to it?

Đây là **Đề thi Violympic – Toán 2 - Vòng 6 vòng tự luyện Năm học 2015 -2016** - Ra ngày 9/11/2015 – Q**uestion 1:** Draw X’s and group them in two ways to illustrate the two ways to multiply. Multiplying in two ways on the number line**Question 2: **For each number line, write the two multiplication sentences that the arrows portray.**Question 3:** Skip-count to fill in the multiplication table of 3. How does the picture relate to it?

Đây là **Đề thi Violympic – Toán 2 - Vòng 5 vòng tự luyện Năm học 2015 -2016** - Ra ngày 26/10/2015 – Q**uestion 1:** Draw X’s and group them in two ways to illustrate the two ways to multiply. Multiplying in two ways on the number line**Question 2: **For each number line, write the two multiplication sentences that the arrows portray.**Question 3:** Skip-count to fill in the multiplication table of 3. How does the picture relate to it?

Đây là **Đề thi Violympic – Toán 2 - Vòng 4 vòng tự luyện Năm học 2014 -2015** - Ra ngày 12/10/2015 – Q**uestion 1:** Draw X’s and group them in two ways to illustrate the two ways to multiply. Multiplying in two ways on the number line**Question 2: **For each number line, write the two multiplication sentences that the arrows portray.**Question 3:** Skip-count to fill in the multiplication table of 3. How does the picture relate to it?

Đây là **Đề thi Violympic – Toán 2 - Vòng 3 vòng tự luyện Năm học 2014 -2015** - Ra ngày 28/09/2015 – Hand your child a large handful of your counting items, a piece of paper and pencil. Explain that they are going to be using them to help them with addition and subtraction. Write the following addition problem on the board (if you do not have a board write it on a large sheet of paper and show it to your child) and have him copy it on their sheet of paper. 28 + 8 =

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Đây là **Đề thi Violympic – Toán 2 - Vòng 1 vòng tự luyện Năm học 2014 -2015** - Ra ngày 05/09/2015 – Hand your child a large handful of your counting items, a piece of paper and pencil. Explain that they are going to be using them to help them with addition and subtraction. Write the following addition problem on the board (if you do not have a board write it on a large sheet of paper and show it to your child) and have him copy it on their sheet of paper. 28 + 8 =

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Đây là **Đề thi Violympic – Toán 2 - Vòng2 vòng tự luyện Năm học 2014 -2015** - Ra ngày 14/09/2015 – For example, in the picture on the right, there is a combination of three apples and two apples together; making a total of 5 apples.

This observation is equivalent to the mathematical expression "3 + 2 = 5" i.e., "3 add 2 is equal to 5". 12 − 9 = ? The problem of subtraction is to name the number we must add to the smaller number so that their sum will equal the larger number. How could you know that 12 minus 9 is 3? Because you know that 9 plus 3 is 12.

That is, you know elementary addition. We will now present two methods of written subtraction. One is the familiar subtraction by regrouping, or borrowing. The other is the less familiar but simpler method of adding to both numbers. It is taught in many countries, and is based on the following property of subtraction: If we add the same number to both the larger and the smaller, the difference will not change.

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