Addition & Subtraction Meanings
What is an addend?
How can you use the breaking apart method to break apart the number 36.
30+6
Round this number to the nearest ten: 61
60
If both addends are rounded up, will the estimate be greater than or less than the actual sum?
Greater than the actual sum.
Think about how many students are in this school. What is a REASONABLE answer?
400-800
What property of addition is being shown here?
19+0=19
Identity (Zero) Property of Addition
Use the breaking apart method to write this number: 78
70+8
Round this number to the nearest hundred: 251
300
Round to the nearest tens to estimate the sum:
28+46
30+50=80
1 student, 10 students, 1,000,000 students, etc.
What is the missing number?
__+8=8+2
2
Use breaking apart to add 25+12. Show me how you broke the numbers apart on your answer.
10+2=12
20+5=25
20+10=30
2+5=7
30+7=37
Round this number to the nearest thousand: 8,993
9,000
Round to the nearest hundred to estimate the sum:
114+58
100+100=200
Carl practices piano 45 minutes each day. Today, he practiced 15 minutes after school and 10 minutes before dinner. How much time does he still need to practice?
A: 70 minutes
B: 60 minutes
C: 35 minutes
D: 20 minutes
D: 20 minutes
The Jet Propulsion Lab had 9 missions between 2003 and 2006. Two of these missions were to study comets. How many of these missions did not study comets?
7 missions
Find the difference using mental math or an algorithm:
29-18
11
Round this number to the nearest ten: 342
340
Round to the nearest ten to estimate the difference:
579-214
580-210=370
Carrie has 15 pennies. Her brother has 10 more pennies than Carrie. How many pennies do they have in all?
A: 40 pennies
B: 25 pennies
C: 10 pennies
D: 5 pennies
A: 40 pennies
Show me an example of the associative property of addition.
(a+b)+c=a+(b+c)
Find the difference using mental math or an algorithm:
97-14
83
Round this number to the nearest hundred: 2,572
2,600
Round to the nearest hundred to estimate the difference:
704-369
700-400=300
Henry is reading a book that is 85 pages long. HE read 35 pages yesterday and 24 pages today. How many pages did James read in the two days?
35+24=59 pages