WEBVTT 00:00:01.340 --> 00:00:04.310 David and Jennifer were building houses out of blocks. 00:00:05.110 --> 00:00:07.760 David used 36 blocks. 00:00:08.710 --> 00:00:11.150 Jennifer used 51 blocks. 00:00:12.040 --> 00:00:13.710 How many blocks did they use? 00:00:15.030 --> 00:00:16.740 Then, we’re asked three questions. 00:00:17.850 --> 00:00:22.450 Will the answer be bigger or smaller than the numbers in the question? 00:00:23.790 --> 00:00:27.740 Do you need to add or subtract to find the answer? 00:00:28.890 --> 00:00:31.240 Find out how many blocks they need. 00:00:33.220 --> 00:00:39.580 This problem asks us to find the total number of blocks that both David and Jennifer use altogether. 00:00:40.550 --> 00:00:47.300 And so the important information in the problem is the number 36 and the number 51. 00:00:48.100 --> 00:00:50.420 These are the amounts that both children use. 00:00:51.870 --> 00:00:56.600 Will the answer be bigger or smaller than the numbers in the question? 00:00:57.560 --> 00:01:00.230 Let’s sketch a bar model to represent the problem. 00:01:01.280 --> 00:01:03.380 Here’s David’s amount of blocks. 00:01:04.820 --> 00:01:08.030 This bar represents the number of blocks that Jennifer uses. 00:01:09.220 --> 00:01:13.350 And the long bar underneath represents the total that we’re looking for. 00:01:14.620 --> 00:01:20.910 So we can see that the answer will be bigger than the numbers in the question because it is the sum of them. 00:01:23.020 --> 00:01:27.740 Our next question asks “Do you need to add or subtract to find the answer?” 00:01:29.050 --> 00:01:31.800 There’re two reasons why we know the answer to this already. 00:01:32.750 --> 00:01:39.920 The first is that, in our bar model, we can see that we need to combine 36 and 51 to find the answer. 00:01:40.790 --> 00:01:44.930 And the second reason is that we know the answer is going to be bigger. 00:01:46.120 --> 00:01:52.480 And because the answer is bigger than the numbers in the problem, we know we need to add to find the answer. 00:01:52.630 --> 00:01:54.930 This is an addition word problem. 00:01:56.060 --> 00:02:04.140 Now that we found the number of blocks that each child has and we know we need to add them together, let’s find out how many blocks they need and solve the problem. 00:02:05.560 --> 00:02:08.630 There’re lots of different ways that we could add these two numbers together. 00:02:08.990 --> 00:02:10.930 Let’s just go through one method now. 00:02:11.990 --> 00:02:17.190 And we know that when we add numbers together, we can add them in any order and the total remains the same. 00:02:17.810 --> 00:02:22.210 Because 36 is the smaller number, let’s start with the larger number. 00:02:22.660 --> 00:02:24.330 Now, we don’t need to add on as many. 00:02:25.450 --> 00:02:32.420 The next thing we can do is to split or to partition the number 36 into tens and ones. 00:02:33.500 --> 00:02:37.250 36 is the same as 30 and six. 00:02:38.380 --> 00:02:41.030 Now, we can add each part to 51. 00:02:42.340 --> 00:02:47.150 51 plus 30 equals 81. 00:02:48.550 --> 00:02:49.960 And now, we’ll add the six. 00:02:50.280 --> 00:02:54.770 81 plus six equals 87. 00:02:56.720 --> 00:03:02.070 And so the number of blocks that David and Jennifer use altogether is 87. 00:03:03.570 --> 00:03:07.140 36 plus 51 equals 87.