# 2007 M. Tallman When estimating division problems, rounding 2007 M. Tallman When estimating division problems, rounding will not work very well. You must use compatible numbers. numbers Compatible numbers are numbers that contain a basic division fact 8,100 90, 720 8, 144,000 120 2007 M. Tallman Find the compatible numbers in these division 1. 120problems. 4 2. ) 9 3,600 3. 21,000 7

4. 240 6 )4,200 7 5. )35,000 5 6. 7. 320 8 )9,600 8 8. 2007 M. Tallman 12 36 21 24 42 35 32

96 4 9 7 6 7 5 8 8 437 9 1 zero in the quotient

1-0=1 1 0 1 450 9 = 50 Step 1: Look at the first couple of numbers of the dividend and the first Step 2: Find the closest basic division fact to these numbers. 2007 M. Tallman Step 3:

Use the basic fact to change the dividend and divisor in to compatible numbers, 508 7 1 zero in the quotient 1-0=1 1 0 1 490 7 = 70 Step 1: Look at the first couple of numbers of the dividend and the first

Step 2: Find the closest basic division fact to these numbers. 2007 M. Tallman Step 3: Use the basic fact to change the dividend and divisor in to compatible numbers, 7 ) 224 1 zero in the quotient 1 30 7 )210 1

0 Step 1: Look at the first couple of numbers of the dividend and the first 1-0=1 Step 2: Find the closest basic division fact to these numbers. 2007 M. Tallman Step 3: Use the basic fact to change the dividend and divisor in to compatible numbers,

4,324 6 2 zeros in the quotient 2-0=2 1 2 0 1 2 4,200 6 = 70 Step 1: Look at the first couple of numbers of the dividend and the first Step 2: Find the closest basic division fact to

these numbers 2007 M. Tallman Step 3: Use the basic fact to change the dividend and divisor in to compatible numbers, 4 ) 3,10 5 12 80 4 ) 3,200 1 2 2 zeros in the quotien t 2-0=2 0

Step 1: Look at the first couple of numbers of the dividend and the first Step 2: Find the closest basic division fact to these numbers. 2007 M. Tallman Step 3: Use the basic fact to change the dividend and divisor in to compatible numbers, Tip: Do Do Tip: not not

count count the zero zero the in 40. 40. in 5 ) 4,17 5 12 80 5 ) 4,000 1 2 2 zeros in the quotien t 2-0=2 0

Step 1: Look at the first couple of numbers of the dividend and the first Step 2: Find the closest basic division fact to these numbers. 2007 M. Tallman Step 3: Use the basic fact to change the dividend and divisor in to compatible numbers, Estimate 468 8 48 8 =

8 Division Fact:_________ 480 8 = 80 Estimate:____________ 2007 M. Tallman Estimate 5,620 5 55 5 = 11 Division Fact:_________ 5,500 5 = 1,100 Estimate:____________ 2007 M. Tallman Estimate 2,198 4 20 4 = 5 Division Fact:_________

2,000 4 = 500 Estimate:____________ 2007 M. Tallman Estimate 358 12 36 12 = 3 Division Fact:_________ 360 12 = 30 Estimate:____________ 2007 M. Tallman Estimate 1,976 9 18 9 = 2 Division Fact:_________ 1,800 9 = 200 Estimate:____________ 2007 M. Tallman