Marie buys 33 tubs of yogurt, each costing $5.20$5.20. She pays from her account which only has $20$20. How much is left in her account after the purchase?
To find the money remaining in the account, find the total price of the yogurt by multiplying them and then subtract the product from the money in the account.
Since 33 tubs of yogurt were bought, multiply the cost of one to 33
Start by ignoring the decimal points and multiply them normally
5.205.20
==
520520
3×5203×520
==
15601560
Next, count how many place values there are from the decimal point to the right of the two factors.
5.20=5.20=2places2places
There are a total of 22 place value movements to the right of the decimal point.
Get the final product by moving the decimal point of the initial product 22 places to the left.
Hence, the total cost of the tubs of yogurt is $15.60$15.60.
Subtract this value from $20$20 to get the left over amount. Line up the decimal points (point over point).
If there are any blank values to the right of the decimal point, write 00.
22
00
..
00
00
-−
11
55
..
66
00
Subtract as you would whole numbers
22
00
..
00
00
-−
11
55
..
66
00
..
00
Since 00 is less than 66 we will use borrowing to subtract
00 (units digit) == borrow 11 from 22
00 (tenths digit) == borrow 11 from 1010 (units digit)
99
11
1010
1010
22
00
..
00
00
-−
11
55
..
66
00
00
44
..
44
00
Therefore, the money that is left over in Marie’s account is $4.40$4.40
$4.40$4.40
Question 2 of 4
2. Question
A roll of cable has 40m40m worth of cable. If the cable costs $9.85 per metre, how much would the entire roll of cable cost?