Mathematics 5

# Surf for More Math

## Lesson 5 - Communicate About a Choice of Calculation Method

Use these interactive games and activities to encourage students to have fun on the Web while learning how to communicate about a choice of calculation method. Students can try these activities on their own or in pairs.

### Goal

Justify your choice of calculation method and explain each step in solving a problem.

### Builds Upon

Student Book pages 106-107

### Instructions for Use

Adding and Subtracting Mentally lets students practice using mental math strategies to add and subtract.

To use Adding and Subtracting Mentally, select a level of difficulty (green is easy, yellow is difficult, and red is the most difficult) beside either addition or subtraction. Click the "Begin!" button to load the first of ten questions. Enter the answer in the text box and press the "Enter" key. The tally on the screen shows your results.

Interactive Math Flashcards lets students practice solving addition and subtraction problems using mental math or a pencil and paper.

To use Interactive Math Flashcards, select the operation (either addition or subtraction). Then select the minimum and maximum values for the first number in the questions (Operand 1) and for the second number in the questions (Operand 2). Click the "Press me to get started" button to load the first question. Input the answer in the text box and click the "Submit Answer" button. To change the operation or complexity of the problems, click the "Change" button. Feedback is provided for each answer.

Estimation Contraption helps students use an estimation strategy to add numbers together.

To use Estimation Contraption, estimate the sum of the column of numbers and then input the answer in the field below the column. Click "OK" to check if the answer is correct. Try the next question.

Estimating Sums by Rounding allows students to estimate the sum of two numbers by rounding.

To use Estimating Sums by Rounding, scroll down and click the "Start Addition" button. Estimate the sum of the two numbers by rounding and press the numeric button closest to your estimation.

Estimating Differences by Rounding allows students to estimate the difference of two numbers by rounding.

To use Estimating Differences by Rounding, scroll down and click the "Start Subtraction" button. Estimate the difference between the two numbers by rounding and press the numeric button closest to your estimation.

Adding Whole Numbers prompts students to use a paper and pencil to add 4-digit numbers.

To use Adding Whole Numbers, click the "Start Addition" button. Using paper and a pencil, add the numbers, regrouping where necessary. Remember to place the number to be added below the first number so that the thousands, hundreds, tens, and ones places are aligned. Enter your answer in the text box and click the "check" button.