Multiplying by Powers of 10
60 x 103
60,000
Estimate the product of 180 x 586
120,000
2,204 x 6
13,224
Jupiter is about 5 times the distance Earth is from the Sun. Earth is about 93,000,000 miles from the Sun. About how far is Jupiter from the Sun?
465,000,000 miles
Is this an equation? Why or why not?
35 x 12
No, because it doesn't have an equal sign!
75 x 10,000
750,000
Estimate the product of 38 x 249
10,000
138 x 5
690
Each elephant at the zoo eats 125 pounds of food a day. How many pounds of food will 18 elephants eat in a day?
2,250 pounds
An apple contains 109 calories. Last week, John ate 9 bananas. If you were asked to find how many calories he consumed, what equation would represent this problem?
109 x 9 = A
104 x 30
300,000
Is 500 an underestimate or overestimate for the product of 12 and 53?
underestimate
42 x 52
2,184
Martin ran 108 miles last year. Katrina ran 13 times as many miles as Martin last year. How many miles did Katrina run last year?
1,404 miles
Is 4,200 equal to 42 x 1,000?
no
5 x 10?= 50,000
4
Sarah's sales goal is $6,000. She sold 289 tickets for $16 each. She says "Since 300 x 20= 6,000, I made my sales goal. Do you agree? Why or why not?
I do not agree because she rounded both factors up, meaning her estimate is an overestimate and greater than what her actual sales total was.
628 x 33
20,724
The Erie shoe factory makes 245 pairs of shoes a day. The Columbus shot factory makes 34 times as many pairs of shoes a day as the Erie shoe factory. How many pairs of shoes does the Columbus shoe factory make a day?
8,330 pairs of shoes
What is 100?
1
14 x __ = 140,000
10,000
What are two methods for finding estimates?
rounding and using compatible numbers
2,525 x 37
93,425
William travels only on Saturdays and Sundays and has flown 1,020 miles this month. Jason travels every weekday and has flown 1,200 miles this month. If each man travels about the same numbers of miles each day, who travels more miles per day for this month? Explain.
Williams; he travels 2 days a week but has flown almost the same number of miles as Jason, who flies 5 days a week.
Why does everyone get 500 points?
Because math is fun!