Mental Math
Use mental math to solve 206.5 + 106.5 .
What is 313?
Estimate to solve.
502.2 + 102.9
What is 600?
Draw base ten models to add 0.12 + 0.35.
What is 0.47? Drawn as 4 rods and 7 cubes
Little Johnny has 2,985 toy cars in a bucket. Little Johnny takes out 14 cars. His brother, Timmy, takes out 11 cars. How many cars are still in the bucket?
What is 2,960 cars remaining?
Use compatible numbers to solve using mental math 22.4 - 16.2.
What is 15?
Estimate 358 + 293.
What is 700?
Draw base ten model to solve 0.95 - 0.24.
What is 0.71? Drawn as 7 rods and 1 cube
Write the equation and solve.
Lil' Jimmy got money for three straight days for doing chores and odd jobs to help around the house. On Monday, he got 98 dollars. On Tuesday, he received $3.79 and his last day he earned $101.64. How much moolah did he get in all?
What is $98 + $3.79 + $101. 64 = $202.43 ?
Using mental math, find the sum of 15.82 + 24.14.
What is 39.96 ?
Estimate 205.4 - 99.7.
What is 100? or 105
Use base 10 models to solve 0.76 + 0.15.
What is 0.91? Drawn as 9 rods and 1 cube
Write an equation and solve. Little Timmy needs 1.43 cups of sugar for his cake. He only has 1.26 cups. How much more sugar does he need?
What is 1.43 - 1.26 = 0.17 cup ?
Estimate 5.84 - 1.53.
What is 4? Or 4.3
Estimate by rounding 15.92 + 0.85.
What is 16 + 1 = 17?
Use base 10 models to solve 1.25 + 0.55.
What is 1.80, drawn as one square, 8 rods
Solve any way you choose. Johnny went to the grocery store and bought 8.46 ounces of apples. Then he to a different store and bought 5.36 ounces of mangoes. If Johnny needs a total of 15 ounces of fruit, does he have enough?
What is no? He needs 0.82 ounces more of fruit.
Use compatible numbers to solve 11.2 + 8.5 + 9.6 + 10.3.
What is 11+9+10+10=40?
Estimate by rounding 23.24 - 5.85.
What is 23-6=17?
Use base 10 models to solve 3.12 - 2.97.
What is 0.15, drawn as 1 rod and 5 cubes
Ryan want to buy two video games. One costs $35.89 and the other costs $43.65. He estimates the total cost of the two games to be about $80. Is his estimate higher or lower than the actual cost? Explain.
What is higher because Ryan rounds 43.65 to 40 and 35.89 to 40, which is $5 over the actual price for the first video game.