Multiples of 10
3 x 10 =
30
5 x 6 =
30
True or False
and why?
2 X 8 = 8 X 2
True – commutative property
There were 18 seashells lying on the beach. Four of them were broken. Mrs. Bagley and Mrs. Gannon split the unbroken shells between us. How many shells did each of them get?
18 - 4 = 14 ÷ 2 = 7 shells
Solve for the unknown:
N X 7 = 7
N =
N = 1
14 x 10 =
140
24 ÷ 3 =
8
True or False
and why?
4 X 5 X 6 = 6 X 5 X 4
True – Associative Property
Mr. Lopez had 24 pieces of whittle equipment to set up in the gym. Then he asked for 6 more pieces. The equipment was equally divided among 5 sections in the gym. How many pieces did each section get?
24 + 6 = 30 ÷ 5 = 6 awards each
Solve for the unknown:
N X 7 = 7 X 5
N =
N = 5
4 x 40 =
160
18 ÷ 6 = 3
Which of the following equations is not a related fact to the number sentence above?
3 x 6 = 18
3 ÷ 6 = 18
18 ÷ 3 = 6
6 X 3 = 18
b: 3 ÷ 6 = 18
True or False
and why?
16 ÷ 4 = 4 ÷ 16
False; commutative property does not work for division
Mrs. Slitt had 6 boxes of pencils with 10 pencils in each box. She gave out 6 pencils to students who were missing their pencils. How many pencils does Mrs. Slitt have left?
(6 x 10) – 6 = 54 pencils
Solve for the unknown:
3 X r X 7 = 4 X 3 X 7
r =
r = 4
8 x 50 =
400
Which ones do not belong to the fact family?
3 X 8 = 24
24 ÷ 3 = 8
8 ÷ 3 = 24
8 X 3 = 24
24 ÷ 8 = 3
24 X 3 = 8
3 and 6
True or False
and why?
5 ÷ 1 = 1
False; the identity property says p X 1 = p, therefore p ÷ 1 must = p
There were 75 third graders at Bugbee School. 40 of them are girls. On Monday, 4 third grade girls and 8 third grade boys were absent. How many third grade boys were there on Monday?
Choose the equation that best fits with this word problem.
75 ÷ 8 =
(75 – 40) – 12 =
(75 – 40) – 8 =
75 – (40 + 4) – 8 =
c – (75-40) – 8 =
Solve for the unknown:
3 X 4 X 2 = P X 4
P =
P = 6
160 ÷ 10 =
16
Solve and explain a strategy for
9 X 8 = h
72; strategies will vary
True or False
and why?
8 X 14 = (8 X 10) + (8 X 4)
True, you can split a factor and use the distributive property
I have $3.99 in my pocket. I bought 4 apples for 49 cents each. Use mental math and estimation to figure out about how much money I have left.
around $2.00
around $1.00
around $3.00
No more money left.
a – around $2.00
Solve for the unknown:
5 X 12 = 5 X (10 + L)
L =
L = 2