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Coursebook Recap

Add 3,243 and 2,324. 3,243 + 2,324 = 5,567

1 Add the ones.

+ 642e)6,909 + 3,090f)6,557 + 1,022

+ $1,327h)$6,415 + $3,283i)$1,683 + $8,204

Coursebook Recap

Add 5,633 and 2,195.

1 Add the ones.

1. Add.

2 Add the

3 Add the hundreds. 4 Add the thousands.

Coursebook Recap

Add 3,456 and 4,782. 3,456 + 4,782 = 8,238

1 Add the ones.

1. Add.

Coursebook Recap

Add 2,567 and 6,844. 2,567 + 6,844 = 9,411

1 Add the ones.

1. Add.

Exercise 1.5 Estimating sums

Coursebook Recap

Find the sum of 2,567 and 6,391.

Estimated sum:

2,567 + 6,391 ≈ 3,000 + 6,000 = 9,000

8,958 is about 9,000. The answer is reasonable.

1. Estimate and then find the actual sum. Use your estimates to check if your answers are reasonable.

a) 5,386 + 3,629 ≈ + = 5,386 + 3,629 =

Is your answer reasonable?

b) 1,987 + 3,794 ≈ + = 1,987 + 3,794 =

Is your answer reasonable?

a)367 + 432

b)298 + 3,490

c)4,601 + 2,740

d)3,295 + 5,454

e)$2,879 + $220

f)$5,166 + $2,543

g)$7,139 + $2,341

$2,900 + $200 = $3,100

$5,200 + $2,500 = $7,700

Actual sum: 2,567 + 6,391 = 8,958 9,015 Estimates vary. Sample: Estimates vary. Sample: Yes 5,781 Yes $3,099 $7,709 $9,480 8,749 7,341 3,788 799 370 + 430 = 800 300 + 3,500 = 3,800 5,000 + 3,000 = 8,000 3,000 + 5,000 = 8,000

2. Estimate and then find the actual sum. Use your estimates to check if your answers are reasonable.

$7,000 + $2,000 = $9,000 5,0004,0009,000 4,0006,000 2,000

Exercise 1.6 Solving word problems

Solve the word problems. Show your work clearly.

1. Understand 2. Plan 3. Answer 4. Check 5. Plus

1. A toy shop sold 4,678 toys last year and 5,111 toys this year. How many toys were sold in the two years altogether?

3. A heat pump costs $5,650. A piano costs $199 more than the heat pump. A refrigerator costs $8,150. How much does the piano cost? ? 4,678 5,111

4,678 + 5,111 = 9,789 9,789 toys were sold in the two years altogether. ? 4,567 1,564

2. A company sent out 4,567 emails on Monday and 1,564 emails on Tuesday. How many emails were sent out on the two days altogether?

4,567 + 1,564 = 6,131 6131 emails were sent out on the two days altogether.

$5,650 $199 heat pump piano

$5,650 + $199 = $5,849 The piano costs $5,849. ?

4. Mrs Taylor bought a dishwasher and a washing machine. The cost of the dishwasher was $1,999. The cost of the washing machine was $215 more than the cost of the dishwasher. What was the cost of the washing machine?

$1,999 $215

dishwasher washing machine ?

$1,999 + $215 = $2,214 The cost of the washing machine was $2,214.

5. On Sunday, 5,345 women and 2,005 men attended a rugby league event. On Saturday, 1,450 more women attended the rugby league event. How many women attended the rugby league event on Saturday?

5,345 + 1,450 = 6,795

Coursebook Recap

Find the difference between 6,051 and 3,645.

Estimated difference:

6,051 – 3,645 ≈ 6,000 – 4,000 = 2,000

2,406 is about 2,000. The answer is reasonable.

1. Estimate and then find the actual difference. Use your estimates to check if your answers are reasonable.

a) 7,934 – 5,621 ≈ – = 7,934 – 5,621 =

Actual difference: 6,051 – 3,645 = 2,406 2,313

Is your answer reasonable?

b) 9,044 – 4,409 ≈ – = 9,044 – 4,409 =

Is your answer reasonable?

Estimates vary. Sample:

a)456 – 321

b)5,768 – 780

c)8,435 – 6,679

d)5,980 – 4,982

e)$3,213 – $2,111

f)$9,453 – $5,032

g)$7,198 – $2,431

Estimates vary. Sample: Yes 4,635 Yes 460 – 320 = 140 5,800 – 800 = 5,000 8,000 – 7,000 = 1,000 6,000 – 5,000 = 1,000

$7,000 – $2,000 = $5,000 8,0006,0002,000 4,0005,000 9,000 $1,102 $4,421 $4,767 998 1,756 4,988 135

2. Estimate and then find the actual difference. Use your estimates to check if your answers are reasonable.

Estimated differenceActual difference

$3,000 – $2,000 = $1,000

$9,000 – $5,000 = $4,000

Exercise 2.7 Solving word problems

Solve the word problems. Show your work clearly.

1. Understand 2. Plan 3. Answer 4. Check 5. Plus

1. Mr Barclay spent $4,567 during his trip to Australia in October. He spent $6,789 during his trip to Fiji in November. How much more did he spend on his trip to Fiji than on his trip to Australia?

$4,567 ? Australia Fiji

$6,789

$6,789 – $4,567 = $2,222 He spent $2,222 more on his trip to Fiji than on his trip to Australia.

2. Sam and Joseph scored a total of 6,733 points in a game. Sam scored 5,670 points. How many points did Joseph score?

6,733 – 5,670 = 1,063 Joseph scored 1,063 points.

3. A vacuum cleaner costs $1,510. A camera costs $1,699. A laptop costs $1,789. How much more does the laptop cost than the camera?

$1,699 ?

$1,789 – $1,699 = $90 The laptop costs $90 more than the camera.

4. In a particular year, a university teaching course had 5,990 students and 109 lecturers. In the next year, 1,762 students left the course. How many students were there in the course in the second year?

? 1,762

5,990 – 1,762 = 4,228

There were 4,228 students in the course in the second year. 5,990 3,323 1,234

5. In a poultry farm, there were 3,323 hens and 2,344 roosters. 1,234 hens were sold on Sunday. How many hens were left?

3,323 – 1,234 = 2,089 2,089 hens were left. ?

6. Town X has 9,989 people, out of which 5,649 are men. Town Y has 230 fewer men and 345 fewer women than town X. How many men are there in town Y?

5,649 – 230 = 5,419

There are 5,419 men in town Y. 5,649 ?

Unit 3 Number Sentences

Exercise 3.1 True or false number sentences involving addition and subtraction

Coursebook Recap

Is 1,362 + 890 = 3,261 – 1,009 true or false?

1,362 + 890 = 2,252

3,261 – 1,009 = 2,252

So, 1,362 + 890 = 3,261 – 1,009 is true. When both sides of the equal sign give the same answer, the number sentence is true.

1. Are the number sentences true or false? Show your work clearly. Then, write true or false in each blank.

a) 7,454 + 972 = 8,426 b) 1,234 – 46 = 5,281 – 4,193

7,454 + 972 = 8,426 1,234 – 46 = 1,188 5,281 – 4,193 = 1,088

7,454 + 972 = 8,426 is . 1,234 – 46 = 5,281 – 4,193 is . c) 5,127 – 2,380 = 1,291 + 1,381 d) 2,102 + 2,989 = 9,000 – 3,909

5,127 – 2,380 = 2,747 1,291 + 1,381 = 2,672 2,102 + 2,989 = 5,091 9,000 – 3,909 = 5,091 true false false true

5,127 – 2,380 = 1,291 + 1,381 2,102 + 2,989 = 9,000 – 3,909 is is . .

2. Write a true number sentence involving addition and subtraction involving 4-digit numbers. Chapter 3: Practice 3.1

Answer varies. Sample: 8,293 – 3,171 = 4,120 + 1,002

Exercise 3.2 Completing open number sentences involving addition and subtraction

Coursebook Recap

3,124 + 1,875 = – 1,238

Find the value of .

3,124 + 1,875 = – 1,238 4,999 = – 1,238 = 4,999 + 1,238 = 6,237

The value of is 6,237.

4,999 1,238 4,143 = 2,487 + ✧

1. Find the missing values. Show your work clearly. a) 3,481 = 2,927 + ☼ ☼ b) 3,182 = 7,290 – Δ ☼ = Δ = c) 3,692 + 2,121 = 4,457 + ✿ d) 8,000 – 2,465 = 8,936 –✿ = = e) 7,126 – 2,983 = 2,487 + ✧ f) 6,287 + 2,125 = 9,465 – ◇ ✧ = ◇ =

✧ = 4,143 – 2,487 = 1,656 8,412 = 9,465 – ◇ ◇ = 9,465 – 8,412 = 1,053 5,813 = 4,457 + ✿

✿ = 5,813 – 4,457 = 1,356 5,535 = 8,936 –= 8,936 – 5,535 = 3,401

☼ = 3,481 – 2,927 = 554 Δ = 7,290 – 3,182 = 4,108 554 4,108 1,656 1,053 1,356 3,401

Unit 4 Problem Solving Exercise 4.1 Word problems

Solve the word problems. Show your work clearly.

2. Mr Smith sold two computers for $6,919. The cost of one computer was $2,274. What was the difference in the cost of the two computers? 1. Understand 2. Plan 3. Answer 4. Check 5. Plus

1. Noah has 2,418 rugby cards. Luka has 597 fewer rugby cards than Noah. How many rugby cards do they have altogether?

2,418 – 597 = 1,821 Luka has 1,821 rugby cards.

2,418 + 1,821 = 4,239 They have 4,239 rugby cards altogether.

$6,919 – $2,274 = $4,645 The cost of the other computer was $4,645.

$4,645 – $2,274 = $2,371

The difference in the cost of the two computers was $2,371.

3. A chocolate factory produced 5,333 chocolates in a week. It produced 1,229 fewer chocolates in the next week. How many chocolates did the factory produce in the two weeks?

5,333 – 1,229 = 4,104

The factory produced 4,104 chocolates in the next week.

5,333 + 4,104 = 9,437

The factory produced 9,437 chocolates in the two weeks.

4. The school supply cupboard has 9,999 small, medium and large paper clips. There are 5,540 small paper clips. There are 3,450 more small paper clips than large paper clips. How many small and large paper clips are there?

5,540 – 3,450 = 2,090 There are 2,090 large paper clips.

5,540 + 2,090 = 7,630 There are 7,630 small and large paper clips.

5. Grace’s monthly salary is $2,456. Eva’s salary is $1,342 less than Grace’s salary. Georgia’s salary is $2,100 more than Eva’s salary. How much is Grace’s and Eva’s salary altogether?

$1,342

$2,456 – $1,342 = $1,114 Eva’s salary is $1,114.

$2,456 + $1,114 = $3,570

Grace’s and Eva’s salary is $3,570 altogether.

6. At a two-day bake sale, 3,525 brownies were sold. 1,452 brownies were sold on the first day. How many more brownies were sold on the second day than on the first day?

3,525 – 1,452 = 2,073 2,073 brownies were sold on the second day.

2,073 – 1,452 = 621 621 more brownies were sold on the second day than on the first day. 1,452 ? ? first day second day 3,525