Subtraction
Subtract: 6,402 - 3,178
3,224
22cm
460
John has 235 baseball cards. He gives 48 to his friend. How many does he have left?
235 - 48 = 187
When rounding, if the number to the right of the place value is between 0 and 4 ("4 or less"), we ______
"Let it rest", Stay the same, or Round Down
Find the difference: 8,000 - 2,349
5,651
A square has side lengths 12 in. What is the perimeter?
48 in
Round 3,749 to the nearest hundred.
3,700
A ribbon is 125 cm long. You cut off 45 cm. How much ribbon remains?
125 - 45 = 80 cm
Why does perimeter use addition and not multiplication?
Answer Varies. Perimeter adds all side lengths to find the total length around a shape. Multiplication is to find the area of the inside of a shape.
Subtract: 7,203 - 4,586
2,617
Find the perimeter of a triangle with side lengths of 12 in, 13 in, and 8 in.
33 in
Round 5,876 to the nearest ten.
5,880
Classroom A has 28 students. Classroom B has 19 students. What is the difference between Classroom A and Classroom B?
28 - 19 = 9 students
How do we regroup/borrow? For example: 23 - 8, how would we solve this?
Answer Varies. "Go next door, borrow ten more"
Subtract: 4,572 - 1,359
3,213
4 m
Round 6,284 to the nearest thousand.
6,000
A garden is rectangular, with the length measuring 15 meters and width of 7 meters. If you put a fence around this garden, how many meters of fence will you need?
Perimeter: 15 + 15 + 7 + 7 = 44 meters
What are some strategies for subtracting large numbers?
Answer Varies. Make sure place values are lined up, keep clean work to keep track of where you are at, etc.
Multi-Step Subtraction: A store had 12,345 pencils. They sold 4,678 the first week and 3,559 the second week. How many pencils remain?
4,108 pencils
The perimeter of a triangle is 45 cm. One side is 10 cm. Another side is 15 cm. What is the third side length?
20 cm
1,870
Mya had $120. She bought school supplies for $38 and a book for $14. How much money does she have left?
120 - 38 - 14 = $68
How can rounding help to estimate answers to check problems?
Answer Varies. Rounding will give an answer close to what the true answer will be.
Example: 128 - 21. 128 rounds to 130, 21 rounds to 20. Estimating, 130 - 20 would be 110, so our answer should be close to 110. 128 - 21 = 107 which is close to 110.