Estimation/Find the Products
Round the factors and estimate the products.
325 x 454 ≈ __________ x __________ = 150,000
What is 300x500 ?
Multiply using any method.
21 x 23
What is 483?
Multiply using any method.
143 x 12
What is 1,716?
Draw a model. Then, write the numerical expressions.
The difference between 8 forty-sevens and
7 forty-sevens
What is (8x47)-(7x47)
43 × 30
Think: 43 ones × 3 tens
What is 1,290
Round the factors and estimate the products.
656 × 106 ≈ __________ x __________ = __________
What is 70,000?
Juwad picked 30 bags of apples on Monday and sold them at his fruit stand for $3.45 each. The following week he picked and sold 26 bags.
a. How much money did Juwad earn in the first week?
What is
Juwad earned 103.50 in the first week.
Multiply using any model.
783 x 42
What is 32,886
Compare the two expressions using >, <, or =. Explain your answer.
62 × (70 + 8) (70 + 8) × 26
What is
The left expression is 62 copies of 70+8. The right expression is 26 copies of 70+8.
Solve using mental math. Draw a tape diagram and fill in the blanks to show your thinking.
49 × 11 = __________ elevens
Think: 50 elevens – 1 eleven
What is 539?
= (__________ × 11) – (__________ × 11)
= __________ – __________
= __________
Find the Products. Hint : Use parenthesis and focus on place value).
1,400 × 20
What is 28,000.
Draw an area model, and then solve using the standard algorithm.
49 × 65
What is 3,185
Draw an area model. Then, solve using the standard algorithm
642 × 207
What is 132,894
b. How much money did he earn in the second week?
What is
Juwad earned 89.70 in the second week.
Determine if these equations are true or false.
a. 35 hundreds = 5 tens × 7 tens
b. 770 × 6 = 77 × 6 × 100
C. 24 × 10 × 90 = 90 × 2,400
What is
A. True
B. False
C. False
Explain how knowing 50 × 4 = 200 helps you find 500 × 400.
What is
Compared to 50x4, 500x400 has 3 additional zeros. So its answer will also have 3 additional zeros.
Draw an area model, and then solve using the standard algorithm.
143 × 12
What is 1716?
Draw an area model. Then, solve using the standard algorithm
642 × 257
What is 164,994
How much did Juwad earn selling bags of apples these two weeks?
What is
Juwad earned 193.20 in the two weeks.
Estimate the product first. Solve by using the standard algorithm. Use your estimate to check the reasonableness of the product.
2,803 × 406
What is 1,138,018
Round the factors and estimate the products.
8,633 × 57,008 ≈
What is 513,000,000
Draw a model. Then, write the numerical expressions.
The sum of 21 and 4, doubled
What is
2x(21+4)
Estimate the product first. Solve by using the standard algorithm. Use your estimate to check the
reasonableness of the product.
283 × 416
What is 117,728
d. Extension: Each bag Juwad picked holds 15 apples. How many apples did he pick in two weeks?
Write an expression to represent this problem.
What is
(30+26)15
Complete the table using your understanding of place value and knowledge of rounding to estimate the product.
Factors
a. 3,409 × 73
b. 82,290 × 240
c. 893 hundreds × 85 tens
a. 3000x70=16,000,000
b. 80,000x200=400,000
c. 900,000x900=81,000,000