Multiplication
What is 30 × 4?
120
Estimate: 26 × 6. Choices: 100, 150, 200, 250
150 (26 is about 25, 25×6=150)
Which is greater: 5/6 or 2/3?
5/6
0.50 ___ 0.05
0.50 > 0.05
Area of 24 ft × 49 ft lawn?
1,176 square feet
Solve 24 × 8
192
Estimate: 49 × 31. Choices: 1,200, 1,300, 1,400, 1,500
1,500 (50×30=1500)
Name 2 fractions equal to 2/3
Examples: 4/6, 6/9, 8/12
0.29 ___ 0.3
0.29 < 0.3
Add 24×49 and 6×23 lawns
24×49 = 1,176, 6×23 = 138, total = 1,314 square feet
Solve 249 × 4
996
Is 1,000 a good estimate for 24×49 and 6×23?
Yes, it's close. 24×49 ≈ 25×50 = 1,250; 6×23 ≈ 6×25 = 150. Total ≈ 1,400
Compare 1/3 and 1/2
1/3 < 1/2
0.6 ___ 0.63
0.6 < 0.63
Write an equation with a variable
24×49 + 6×23 = a
Solve 642 × 5
3,210
Estimate 12 × 56
About 600 (12×56 ≈ 10×60 = 600)
Which is greater: 4/6 or 3/4? Prove it.
3/4 is greater. 4/6 = 2/3 (approx. 0.67), 3/4 = 0.75
2/10 ___ 25/100
0.2 < 0.25
Use a model to solve lawn area
Diagram shows 2 rectangles: 24×49=1,176, 6×23=138; total = 1,314
Choose one: 12×14, 15×13, 22×23, 26×23, 38×27, 87×56
12×14 = 168,
15×13 = 195,
22×23 = 506,
26×23 = 598,
38×27 = 1,026,
87×56 = 4,872
Estimate 38 × 27
About 1,000 (40×25 = 1,000)
Label number line with fractions & decimals
Varies. Example: 1/2 = 0.5, 1/4 = 0.25, 3/4 = 0.75, 2/10 = 0.2
Max: 4/10 + 35/100 = 39/100
Ari: 4/10 + 35/100 = 75/100
Who is right?
Ari is right.
4/10 = 40/100,
40/100 + 35/100 = 75/100
Why is Molly’s 1,000 sq ft estimate off?
She underestimated. Estimate: 25×50 + 5×25 = 1,250 + 125 = 1,375