Math Vocab.
You can replace the values in a problem with _________________ so that it's easier to use mental math to complete the computation.
Word Bank: Associative Property of Addition, Commutative Property of Addition, compatible numbers, equivalent decimals, inverse operations
What are compatible numbers.
Solve the following using mental math:
8.6 + 23.4 + 1.4 =
Answer: 33.4
Estimate the numbers to find the answer:
358 + 293
Hint: Round them to the nearest hundred!
Answer: 400 + 300 = 700
Add the decimals using the rules:
0.02 + 0.89 =
Answer: 0.91
Subtract the decimals using the rules:
0.67 - 0.31
Answer: 0.36
Because of the ___________________________. I know that 477.75 + (76.89 + 196.25) = (76.89 + 196.25) + 477.75 without adding.
Word Bank: Associative Property of Addition, Commutative Property of Addition, compatible numbers, equivalent decimals, inverse operations
What is Commutative Property of Addition.
Solve the following using mental math:
27 - 9.9 =
Answer: 17.1
Estimate the numbers to find the answer:
15.01 - 4.4 =
Hint: Round the ones place.
Add the decimals using the rules:
0.34 + 0.34 =
Answer: 0.68
Subtract the decimals using rules:
8.71 - 0.4 =
Answer: 8.31
To align decimal points in a decimal addition problem, annex zeros to write ___________________ so that all the addends have the same number of decimal places.
Word Bank: Associative Property of Addition, Commutative Property of Addition, compatible numbers, equivalent decimals, inverse operations
What are equivalent decimals.
Solve the following using mental math:
13.5 + 5.7 + 36.5 =
Answer: 55.7
Estimate the numbers to find the answer:
80.01 + 2.89 =
Hint: Round to the nearest whole number.
Answer: 80 + 3 = 83
Add the decimals using the rules:
7.06 + 0.85 =
Answer: 7.91
Subtract the decimals using rules:
24.07 - 5.316 =
Answer: 18.754
The ________________________ states that addends can be regrouped and the sum remains the same.
Word Bank: Associative Property of Addition, Commutative Property of Addition, compatible numbers, equivalent decimals, inverse operations
What is the Associative Property of Addition.
Solve the following using mental math:
20.45 + 12.55 =
Answer: 33
Estimate the numbers to find the answer:
1,453.6 - 648.2 =
Hint: Round to the nearest hundred.
Answer: 1,500 - 600 = 900
Add the decimals using the rules:
98 + 3.79 =
Answer: 101.79
Subtract the decimals using rules:
51.92 - 28.003 =
Answer: 23.917
What are the steps that we need to take in order to add or subtract decimals? (List them in order)
What are:
1) Line the decimals up or stack them on top of each other.
2) Add zeros in for place holders if needed.
3) Add or Subtract starting with the number farthest to the right and working over to the left. Carry or borrow if needed.
Solve the following using mental math:
205.4 - 99.7 =
Answer: 105.7
Estimate the numbers to find the answer:
25,003 - 12,900 =
Hint: Round to the nearest thousand.
Answer: 25,000 - 13,000 = 12,000
Solve the word problem:
Alberto ran 15.6 km on Monday, 12.8 km on Tuesday, and 6.5 km on Wednesday. Dennis ran 11.25 km on Monday, 14.6 km on Tuesday, and 8 km on Wednesday. Who ran farther?
Answer:
Alberto- 15.6 + 12.8 + 6.5 = 34.9
Dennis- 11.25 + 14.6 + 8 = 33.85
Alberto ran farther.
Solve the word problem:
Talia measured two strings. The green string was 2.37 cm long. The blue string was 4 cm long. How many centimeters longer was the blue string than the green string?
Answer: 4.00 - 2.37 = 1.63